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Samudrala K, Akram MO, Dutton JL, Martin CD, Conley MP. Formation of Strong Boron Lewis Acid Sites on Silica. Inorg Chem 2024; 63:4939-4946. [PMID: 38451151 PMCID: PMC10951953 DOI: 10.1021/acs.inorgchem.3c04121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024]
Abstract
Bis(1-methyl-ortho-carboranyl)borane (HBMeoCb2) is a very strong Lewis acid that reacts with the isolated silanols present on silica partially dehydroxylated at 700 °C (SiO2-700) to form the well-defined Lewis site MeoCb2B(OSi≡) (1) and H2. 11B{1H} magic-angle spinning (MAS) nuclear magnetic resonance (NMR) data of 1 are consistent with that of a three-coordinate boron site. Contacting 1 with O═PEt3 (triethylphosphine oxide TEPO) and measuring 31P{1H} MAS NMR spectra show that 1 preserves the strong Lewis acidity of HBMeoCb2. Hydride ion affinity and fluoride ion affinity calculations using small molecules analogs of 1 also support the strong Lewis acidity of the boron sites in this material. Reactions of 1 with Cp2Hf(13CH3)2 show that the Lewis sites are capable of abstracting methide groups from Hf to form [Cp2Hf-13CH3][H313C-B(MeoCb2)OSi≡], but with a low overall efficiency.
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Affiliation(s)
| | - Manjur O. Akram
- Department
of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Jason L. Dutton
- Department
of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Caleb D. Martin
- Department
of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Matthew P. Conley
- Department
of Chemistry, University of California, Riverside, California 92521, United States
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2
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Akram MO, Martin CD, Dutton JL. The Effect of Carborane Substituents on the Lewis Acidity of Boranes. Inorg Chem 2023; 62:13495-13504. [PMID: 37560972 DOI: 10.1021/acs.inorgchem.3c01872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
The Lewis acidity of primary, secondary, and tertiary boranes with phenyl, pentafluorophenyl, and all three isomers of the C-substituted icosahedral carboranes (ortho, meta, and para) was investigated by computing their fluoride, hydride, and ammonia affinities as well as their global electrophilicity indices and LUMO energies. From these calculations, it was determined that the substituent effects on the Lewis acidity of these boranes follow the trend of ortho-carborane > meta-carborane > para-carborane > C6F5 > C6H5.
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Affiliation(s)
- Manjur O Akram
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, Texas 76798, United States
| | - Caleb D Martin
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, Texas 76798, United States
| | - Jason L Dutton
- La Trobe University, Department of Chemistry, La Trobe Institute for Molecular Science, Melbourne, Victoria 3086,Australia
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3
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Akram MO, Tidwell JR, Dutton JL, Martin CD. Bis(1-Methyl-ortho-Carboranyl)Borane. Angew Chem Int Ed Engl 2023; 62:e202307040. [PMID: 37338991 DOI: 10.1002/anie.202307040] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/22/2023]
Abstract
The Lewis superacid, bis(1-methyl-ortho-carboranyl)borane, is rapidly accessed in two steps. It is a very effective hydroboration reagent capable of B-H addition to alkenes, alkynes, and cyclopropanes. To date, this is the first identified Lewis superacidic secondary borane and most reactive neutral hydroboration reagent.
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Affiliation(s)
- Manjur O Akram
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
| | - John R Tidwell
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
| | - Jason L Dutton
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, TX, 76798, USA
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4
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Vashisth K, Dutta S, Akram MO, Martin CD. Examining the reactivity of tris( ortho-carboranyl)borane with Lewis bases and application in frustrated Lewis pair Si-H bond cleavage. Dalton Trans 2023. [PMID: 37377440 DOI: 10.1039/d3dt01557b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Reactions of tris(ortho-carboranyl)borane with Lewis bases reveals only small bases bind. The tremendous bulk and Lewis acidity is leveraged in frustrated Lewis pair Si-H cleavage with a wider range of Lewis bases and greater efficacy than B(C6F5)3.
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Affiliation(s)
- Kanika Vashisth
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Sanjay Dutta
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Manjur O Akram
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
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5
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Abstract
The synthesis of tris(ortho-carboranyl)borane (BoCb3 ), a single site neutral Lewis superacid, in one pot from commercially available materials is achieved. The high fluoride ion affinity (FIA) confirms its classification as a Lewis superacid and the Gutmann-Beckett method as well as adducts with Lewis bases indicate stronger Lewis acidity over the widely used fluorinated aryl boranes. The electron withdrawing effect of ortho-carborane and lack of pi-delocalization of the LUMO rationalize the unusually high Lewis acidity. Catalytic studies indicate that BoCb3 is a superior catalyst for promoting C-F bond functionalization reactions than tris(pentafluorophenyl)borane [B(C6 F5 )3 ].
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Affiliation(s)
- Manjur O. Akram
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
| | - John R. Tidwell
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
| | - Jason L. Dutton
- Department of Biochemistry and ChemistryLa Trobe Institute for Molecular ScienceLa Trobe UniversityMelbourneVictoria3086Australia
| | - Caleb D. Martin
- Department of Chemistry and BiochemistryBaylor UniversityOne Bear Place #97348WacoTX 76798USA
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6
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Akram MO, Tidwell J, Dutton J, Martin CD. Tris(ortho‐carboranyl)borane: An Isolable, Halogen‐Free, Lewis Super Acid. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202212073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - John Tidwell
- Baylor University Chemistry and Biochemistry UNITED STATES
| | - Jason Dutton
- La Trobe University - Bundoora Campus: La Trobe University Biochemistry and Chemistry AUSTRALIA
| | - Caleb D. Martin
- Baylor University Chemistry and Biochemistry One Bear Place #97348 76798 Waco UNITED STATES
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Abstract
Borole-doped polycyclic aromatic hydrocarbons (PAHs) have garnered attention in recent years due to their attractive photophysical properties and potential utility in electronic devices. In this work, a borole-doped PAH, 12-boradibenzofluorene, is synthesized and formal intermolecular nitrene and oxygen atom insertion reactions were employed to access 1,2-azaborine- and 1,2-oxaborine-containing analogues of the carbonaceous PAH pentaphene. Iodosobenzene is established as a versatile reagent for oxygen atom insertion reactions into a variety of borole species to access 1,2-oxaborine systems.
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Affiliation(s)
- Manjur O Akram
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - John R Tidwell
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Jason L Dutton
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - David J D Wilson
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Andrew Molino
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
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Sancheti SP, Akram MO, Roy R, Bedi V, Kundu S, Patil NT. ortho-Oxygenative 1,2-Difunctionalization of Diarylalkynes under Merged Gold/Organophotoredox Relay Catalysis. Chem Asian J 2019; 14:4601-4606. [PMID: 31589800 DOI: 10.1002/asia.201901275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 09/30/2019] [Indexed: 02/05/2023]
Abstract
Reported herein is an ortho-oxygenative 1,2-difunctionalization of diarylalkynes under merged gold/organophotoredox catalysis to access highly functionalized 2-(2-hydroxyaryl)-2-alkoxy-1-arylethan-1-ones. Detailed mechanistic studies suggested a relay process, initiating with gold-catalyzed hydroalkoxylation of alkynes, to generate enol-ether followed by a key formal [4+2]-cycloaddition reaction. The successful application of the present methodology was also shown for the synthesis of benzofurans.
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Affiliation(s)
- Shashank P Sancheti
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462 066, India
| | - Manjur O Akram
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411 008, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110 025, India
| | - Rupam Roy
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462 066, India
| | - Vaibhav Bedi
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462 066, India
| | - Shubhankar Kundu
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462 066, India
| | - Nitin T Patil
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462 066, India
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Affiliation(s)
- Manjur O. Akram
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Avishek Das
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal 462 066, India
| | - Indradweep Chakrabarty
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India
- Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Nitin T. Patil
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal 462 066, India
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10
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Akram MO, Shinde PS, Chintawar CC, Patil NT. Gold(i)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes. Org Biomol Chem 2018; 16:2865-2869. [DOI: 10.1039/c8ob00630j] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Gold(i)-catalyzed cross-coupling reactions of aryldiazonium salts with organostannanes are described.
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Affiliation(s)
- Manjur O. Akram
- Division of Organic Chemistry
- CSIR – National Chemical Laboratory
- Pune – 411 008
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Popat S. Shinde
- Division of Organic Chemistry
- CSIR – National Chemical Laboratory
- Pune – 411 008
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Chetan C. Chintawar
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhopal – 462 066
- India
| | - Nitin T. Patil
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhopal – 462 066
- India
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11
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Chakrabarty I, Akram MO, Biswas S, Patil NT. Visible light mediated desilylative C(sp2)–C(sp2) cross-coupling reactions of arylsilanes with aryldiazonium salts under Au(i)/Au(iii) catalysis. Chem Commun (Camb) 2018; 54:7223-7226. [DOI: 10.1039/c8cc03925a] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Desilylative C(sp2)–C(sp2) cross-coupling reactions of arylsilanes with aryldiazonium salts under Au(i)/photoredox catalysis have been reported.
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Affiliation(s)
- Indradweep Chakrabarty
- Division of Organic Chemistry
- CSIR – National Chemical Laboratory
- Dr Homi Bhabha Road
- Pune
- India
| | - Manjur O. Akram
- Division of Organic Chemistry
- CSIR – National Chemical Laboratory
- Dr Homi Bhabha Road
- Pune
- India
| | - Suprakash Biswas
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhauri
- Bhopal
- India
| | - Nitin T. Patil
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhauri
- Bhopal
- India
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12
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Akram MO, Banerjee S, Saswade SS, Bedi V, Patil NT. Oxidant-free oxidative gold catalysis: the new paradigm in cross-coupling reactions. Chem Commun (Camb) 2018; 54:11069-11083. [DOI: 10.1039/c8cc05601c] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The construction of C–C and C–X (X = hetero atom) bonds is the core aspect for the assembly of molecules. This feature article critically presents an overview of all the redox neutral cross-coupling reactions enabled by gold catalysis, which we believe would stimulate further research activities in this promising area.
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Affiliation(s)
- Manjur O. Akram
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Dr Homi Bhabha Road
- Pune 411 008
- India
| | - Somsuvra Banerjee
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Dr Homi Bhabha Road
- Pune 411 008
- India
| | - Sagar S. Saswade
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhopal – 462 066
- India
| | - Vaibhav Bedi
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhopal – 462 066
- India
| | - Nitin T. Patil
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhopal – 462 066
- India
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13
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Akram MO, Mali PS, Patil NT. Cross-Coupling Reactions of Aryldiazonium Salts with Allylsilanes under Merged Gold/Visible-Light Photoredox Catalysis. Org Lett 2017; 19:3075-3078. [DOI: 10.1021/acs.orglett.7b01148] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Manjur O. Akram
- Division
of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi 110 025, India
| | - Pramod S. Mali
- Division
of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India
| | - Nitin T. Patil
- Division
of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi 110 025, India
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14
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Chakrabarty I, Inamdar SM, Akram MO, Gade AB, Banerjee S, Bera S, Patil NT. [3+2]-Annulation of platinum-bound azomethine ylides with distal C[double bond, length as m-dash]C bonds of N-allenamides. Chem Commun (Camb) 2017; 53:196-199. [PMID: 27917422 DOI: 10.1039/c6cc07874e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A Pt-catalyzed, highly regioselective reaction between N-allenamides and imino-alkynes leading to pyrrolo[1,2-a]indoles is described. This represents the first example of [3+2]-annulation of Pt-bound azomethine ylides with the distal C[double bond, length as m-dash]C bond of N-allenamides. The mechanism of the reaction was established by computational studies.
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Affiliation(s)
- Indradweep Chakrabarty
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India. and Academy of Scientific and Innovative Research (AcSIR), New Delhi - 110025, India
| | - Suleman M Inamdar
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India.
| | - Manjur O Akram
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India. and Academy of Scientific and Innovative Research (AcSIR), New Delhi - 110025, India
| | - Amol B Gade
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India. and Academy of Scientific and Innovative Research (AcSIR), New Delhi - 110025, India
| | - Subhrashis Banerjee
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India
| | - Saibal Bera
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India
| | - Nitin T Patil
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune - 411008, India. and Academy of Scientific and Innovative Research (AcSIR), New Delhi - 110025, India
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15
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Akram MO, Bera S, Patil NT. A facile strategy for accessing 3-alkynylchromones through gold-catalyzed alkynylation/cyclization of o-hydroxyarylenaminones. Chem Commun (Camb) 2016; 52:12306-12309. [DOI: 10.1039/c6cc07119h] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A strategy based on tandem alkynylation ofo-hydroxyarylenaminones followed by intramolecular cyclization has been developed to generate a diverse array of 3-alkynyl chromones.
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Affiliation(s)
- Manjur O. Akram
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Pune-411 008
- India
- Academy of Scientific and Innovative Research (AcSIR)
| | - Saibal Bera
- Academy of Scientific and Innovative Research (AcSIR)
- New Delhi-110 025
- India
- Physical and Materials Chemistry Division
- CSIR-National Chemical Laboratory
| | - Nitin T. Patil
- Division of Organic Chemistry
- CSIR-National Chemical Laboratory
- Pune-411 008
- India
- Academy of Scientific and Innovative Research (AcSIR)
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