1
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Cheung-Lee WL, Kolev JN, McIntosh JA, Gil AA, Pan W, Xiao L, Velásquez JE, Gangam R, Winston MS, Li S, Abe K, Alwedi E, Dance ZEX, Fan H, Hiraga K, Kim J, Kosjek B, Le DN, Marzijarani NS, Mattern K, McMullen JP, Narsimhan K, Vikram A, Wang W, Yan JX, Yang RS, Zhang V, Zhong W, DiRocco DA, Morris WJ, Murphy GS, Maloney KM. Engineering Hydroxylase Activity, Selectivity, and Stability for a Scalable Concise Synthesis of a Key Intermediate to Belzutifan. Angew Chem Int Ed Engl 2024; 63:e202316133. [PMID: 38279624 DOI: 10.1002/anie.202316133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/16/2024] [Accepted: 01/23/2024] [Indexed: 01/28/2024]
Abstract
Biocatalytic oxidations are an emerging technology for selective C-H bond activation. While promising for a range of selective oxidations, practical use of enzymes catalyzing aerobic hydroxylation is presently limited by their substrate scope and stability under industrially relevant conditions. Here, we report the engineering and practical application of a non-heme iron and α-ketoglutarate-dependent dioxygenase for the direct stereo- and regio-selective hydroxylation of a non-native fluoroindanone en route to the oncology treatment belzutifan, replacing a five-step chemical synthesis with a direct enantioselective hydroxylation. Mechanistic studies indicated that formation of the desired product was limited by enzyme stability and product overoxidation, with these properties subsequently improved by directed evolution, yielding a biocatalyst capable of >15,000 total turnovers. Highlighting the industrial utility of this biocatalyst, the high-yielding, green, and efficient oxidation was demonstrated at kilogram scale for the synthesis of belzutifan.
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Affiliation(s)
| | - Joshua N Kolev
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - John A McIntosh
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Agnieszka A Gil
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Weilan Pan
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Li Xiao
- Modeling & Informatics, Discovery Chemistry, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Juan E Velásquez
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Rekha Gangam
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Matthew S Winston
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Shasha Li
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Kotoe Abe
- Chemical Commercialization Technologies, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Embarek Alwedi
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Zachary E X Dance
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Haiyang Fan
- API Process Research & Development (Biocatalysis), Shanghai STA Pharmaceutical Co., Ltd., Shanghai, 201507, China
| | - Kaori Hiraga
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Jungchul Kim
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Birgit Kosjek
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Diane N Le
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | | | - Keith Mattern
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | | | - Karthik Narsimhan
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Ajit Vikram
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Wei Wang
- API Process Research & Development (Biocatalysis), Shanghai STA Pharmaceutical Co., Ltd., Shanghai, 201507, China
| | - Jia-Xuan Yan
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Rong-Sheng Yang
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Victoria Zhang
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Wendy Zhong
- Analytical Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Daniel A DiRocco
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - William J Morris
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Grant S Murphy
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
| | - Kevin M Maloney
- Process Research and Development, Merck & Co., Inc., Rahway, NJ 07065, USA
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2
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Benkovics T, Peng F, Phillips EM, An C, Bade RS, Chung CK, Dance ZEX, Fier PS, Forstater JH, Liu Z, Liu Z, Maligres PE, Marshall NM, Salehi Marzijarani N, McIntosh JA, Miller SP, Moore JC, Neel AJ, Obligacion JV, Pan W, Pirnot MT, Poirier M, Reibarkh M, Sherry BD, Song ZJ, Tan L, Turnbull BWH, Verma D, Waldman JH, Wang L, Wang T, Winston MS, Xu F. Diverse Catalytic Reactions for the Stereoselective Synthesis of Cyclic Dinucleotide MK-1454. J Am Chem Soc 2022; 144:5855-5863. [PMID: 35333525 DOI: 10.1021/jacs.1c12106] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
As practitioners of organic chemistry strive to deliver efficient syntheses of the most complex natural products and drug candidates, further innovations in synthetic strategies are required to facilitate their efficient construction. These aspirational breakthroughs often go hand-in-hand with considerable reductions in cost and environmental impact. Enzyme-catalyzed reactions have become an impressive and necessary tool that offers benefits such as increased selectivity and waste limitation. These benefits are amplified when enzymatic processes are conducted in a cascade in combination with novel bond-forming strategies. In this article, we report a highly diastereoselective synthesis of MK-1454, a potent agonist of the stimulator of interferon gene (STING) signaling pathway. The synthesis begins with the asymmetric construction of two fluoride-bearing deoxynucleotides. The routes were designed for maximum convergency and selectivity, relying on the same benign electrophilic fluorinating reagent. From these complex subunits, four enzymes are used to construct the two bridging thiophosphates in a highly selective, high yielding cascade process. Critical to the success of this reaction was a thorough understanding of the role transition metals play in bond formation.
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Affiliation(s)
- Tamas Benkovics
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Feng Peng
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Eric M Phillips
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Chihui An
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Rachel S Bade
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Cheol K Chung
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Zachary E X Dance
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Patrick S Fier
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Jacob H Forstater
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Zhijian Liu
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Zhuqing Liu
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Peter E Maligres
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Nicholas M Marshall
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Nastaran Salehi Marzijarani
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - John A McIntosh
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Steven P Miller
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Jeffrey C Moore
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Andrew J Neel
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Jennifer V Obligacion
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Weilan Pan
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Michael T Pirnot
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Marc Poirier
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Mikhail Reibarkh
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Benjamin D Sherry
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Zhiguo Jake Song
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Lushi Tan
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Ben W H Turnbull
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Deeptak Verma
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Jacob H Waldman
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Lu Wang
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Tao Wang
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Matthew S Winston
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Feng Xu
- Department of Process Research and Development, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
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3
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Salehi Marzijarani N, Fine AJ, Dalby SM, Gangam R, Poudyal S, Behre T, Ekkati AR, Armstrong BM, Shultz CS, Dance ZEX, Stone K. Manufacturing Process Development for Belzutifan, Part 4: Nitrogen Flow Criticality for Transfer Hydrogenation Control. Org Process Res Dev 2021. [DOI: 10.1021/acs.oprd.1c00231] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
| | - Adam J. Fine
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Stephen M. Dalby
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Rekha Gangam
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Samiksha Poudyal
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Taylor Behre
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Anil R. Ekkati
- Chemical Commercialization Technology, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Brittany M. Armstrong
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - C. Scott Shultz
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Zachary E. X. Dance
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Kevin Stone
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
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4
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Chen Z, Salehi Marzijarani N, Quirie S, Pirrone GF, Dalby SM, Wang T, Kim J, Peng F, Fine AJ. Manufacturing Process Development for Belzutifan, Part 3: Completing a Streamlined Through-Process with a Safe and Scalable Oxidation. Org Process Res Dev 2021. [DOI: 10.1021/acs.oprd.1c00232] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Zhiwei Chen
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | | | - Scott Quirie
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Gregory F. Pirrone
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Stephen M. Dalby
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Tao Wang
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Jungchul Kim
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Feng Peng
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Adam J. Fine
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
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5
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Salehi Marzijarani N, Lam YH, Wang X, Klapars A, Qi J, Song Z, Sherry BD, Liu Z, Ji Y. New Mechanism for Cinchona Alkaloid-Catalysis Allows for an Efficient Thiophosphorylation Reaction. J Am Chem Soc 2020; 142:20021-20029. [PMID: 33180475 DOI: 10.1021/jacs.0c09192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
An efficient synthesis of nucleoside 5'-monothiophosphates under mild reaction conditions using commercially available thiophosphoryl chloride was achieved with a cinchona alkaloid catalyst. A detailed mechanistic study of the reaction was undertaken, employing a combination of reaction kinetics, NMR spectroscopy, and computational modeling, to better understand the observed reactivity. Taken collectively, the results support an unprecedented mechanism for this class of organocatalyst.
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Affiliation(s)
| | - Yu-Hong Lam
- Department of Computational and Structural Chemistry, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Xiao Wang
- Department of Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Artis Klapars
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Ji Qi
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States.,Department of Process Research and Development, MSD R&D (China) Co., Ltd., Building 21 Rongda Road, Wangjing R&D Base, Zhongguancun Electronic Zone West Zone, Beijing 100012, China
| | - Zhiyan Song
- Department of Synthetic Chemistry, Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing 100176, China
| | - Benjamin D Sherry
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Zhijian Liu
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Yining Ji
- Department of Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
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6
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Salehi Marzijarani N, Snead DR, McMullen JP, Lévesque F, Weisel M, Varsolona RJ, Lam YH, Liu Z, Naber JR. One-Step Synthesis of 2-Fluoroadenine Using Hydrogen Fluoride Pyridine in a Continuous Flow Operation. Org Process Res Dev 2019. [DOI: 10.1021/acs.oprd.9b00178] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Nastaran Salehi Marzijarani
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - David R. Snead
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - Jonathan P. McMullen
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - François Lévesque
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - Mark Weisel
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - Richard J. Varsolona
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - Yu-hong Lam
- Modeling and Informatics, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - Zhijian Liu
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
| | - John R. Naber
- Process Research & Development, MRL, Merck & Co. Inc., P.O. Box 2000, Rahway, New Jersey 07065, United States
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7
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Salehi Marzijarani N, Yousefi R, Jaganathan A, Ashtekar KD, Jackson JE, Borhan B. Absolute and relative facial selectivities in organocatalytic asymmetric chlorocyclization reactions. Chem Sci 2018; 9:2898-2908. [PMID: 29719676 PMCID: PMC5896375 DOI: 10.1039/c7sc04430e] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/24/2017] [Indexed: 12/16/2022] Open
Abstract
For four related 1,1-disubstituted olefins, (DHQD)2PHAL-catalyzed asymmetric chlorocyclization delivers Cl+ uniformly to one π face, but cyclizes with strong but differing net syn vs. anti addition.
Though (DHQD)2PHAL-catalyzed chlorocyclizations of 1,1-disubstituted olefins show useful (and in some cases, reversible) asymmetric induction, stereochemically complete descriptions of these alkene additions have remained largely unknown. Herein, based on a combination of NMR, derivative, isotope labeling, and computational studies, we present detailed stereochemical analyses of chlorocyclizations of nucleophile-tethered 1,1-disubstituted styryl systems. The selectivities of the two asymmetric bond-forming processes, namely electrophilic chlorine attack and nucleophilic ring closure, are thus mapped out independently. Under the established optimal conditions, four related chlorocyclizations were subjected to this analysis. All showed a strong preference for Cl+ delivery from the same face of the alkene. However, depending on reaction conditions and substrate identity (carboxylic acid, amide or carbamate), the internal nucleophiles may close with a strong net preference for either syn or anti addition relative to the Cl atom. Studies of both uncatalyzed and (DHQD)2PHAL-catalyzed processes place new boundary conditions on the role of the catalyst in these reactions.
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Affiliation(s)
| | - Roozbeh Yousefi
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , USA . ;
| | - Arvind Jaganathan
- Dow AgroSciences LLC , 9330 Zionsville Road , Indianapolis , IN 46268 , USA
| | - Kumar Dilip Ashtekar
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , USA . ;
| | - James E Jackson
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , USA . ;
| | - Babak Borhan
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , USA . ;
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8
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Ashtekar K, Marzijarani NS, Jaganathan A, Holmes D, Jackson JE, Borhan B. A new tool to guide halofunctionalization reactions: the halenium affinity (HalA) scale. J Am Chem Soc 2014; 136:13355-62. [PMID: 25152188 PMCID: PMC4183602 DOI: 10.1021/ja506889c] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Indexed: 01/15/2023]
Abstract
We introduce a previously unexplored parameter-halenium affinity (HalA)- as a quantitative descriptor of the bond strengths of various functional groups to halenium ions. The HalA scale ranks potential halenium ion acceptors based on their ability to stabilize a "free halenium ion". Alkenes in particular but other Lewis bases as well, such as amines, amides, carbonyls, and ether oxygen atoms, etc., have been classified on the HalA scale. This indirect approach enables a rapid and straightforward prediction of chemoselectivity for systems involved in halofunctionalization reactions that have multiple nucleophilic sites. The influences of subtle electronic and steric variations, as well as the less predictable anchimeric and stereoelectronic effects, are intrinsically accounted for by HalA computations, providing quantitative assessments beyond simple "chemical intuition". This combined theoretical-experimental approach offers an expeditious means of predicting and identifying unprecedented reactions.
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Affiliation(s)
- Kumar
Dilip Ashtekar
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | | | - Arvind Jaganathan
- Engineering
and Process Sciences, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Daniel Holmes
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - James E. Jackson
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Babak Borhan
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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9
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Garzan A, Jaganathan A, Salehi Marzijarani N, Yousefi R, Whitehead DC, Jackson JE, Borhan B. Solvent-dependent enantiodivergence in the chlorocyclization of unsaturated carbamates. Chemistry 2013; 19:9015-21. [PMID: 23671005 DOI: 10.1002/chem.201300189] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/19/2013] [Indexed: 11/06/2022]
Abstract
A remarkable solvent-controlled enantiodivergence is seen in the hydroquinidine 1,4-phthalazinediyl diether ((DHQD)2PHAL)-catalyzed chlorocyclization of unsaturated carbamates. Eyring plot analyses of this previously unreported reaction are used to probe and compare the R- and S-selective pathways. In the CHCl3/hexanes solvent system, the pro-R process shows a surprising increase in selectivity with increasing temperature. These studies point to a strongly solvent-dependent entropy-enthalpy balance between the pro-R and pro-S pathways.
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Affiliation(s)
- Atefeh Garzan
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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10
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Kulshrestha A, Salehi Marzijarani N, Dilip Ashtekar K, Staples R, Borhan B. 3,4-Dihydroxypyrrolidines via Modified Tandem Aza-Payne/Hydroamination Pathway. Org Lett 2012; 14:3592-5. [DOI: 10.1021/ol301204w] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aman Kulshrestha
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | | | - Kumar Dilip Ashtekar
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Richard Staples
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Babak Borhan
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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