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White NA, Clagg K, Sirois LE, Lim NK, Nack WA, O’Shea PD, Zhang H, Gosselin F. Practical Synthesis of a Stable Precursor for Positron Emission Tomography Imaging Agent 18F-GTP1. Org Process Res Dev 2020. [DOI: 10.1021/acs.oprd.0c00301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicholas A. White
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Kyle Clagg
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Lauren E. Sirois
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Ngiap-Kie Lim
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - William A. Nack
- Exemplify BioPharma, 3000 Eastpark Boulevard, Suite 500-A, Cranbury, New Jersey 08512, United States
| | - Paul D. O’Shea
- Exemplify BioPharma, 3000 Eastpark Boulevard, Suite 500-A, Cranbury, New Jersey 08512, United States
| | - Haiming Zhang
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Francis Gosselin
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
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2
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White NA, Clagg K, Sirois LE, Mack KA, Al-Sayah MA, Nack WA, O'Shea PD, Zhang H, Gosselin F. Phosphoramidates as Steering Elements for Highly Selective Access to Complementary Imidazo[1,2- a]pyrimidine Isomers. Org Lett 2019; 21:9527-9531. [PMID: 31738563 DOI: 10.1021/acs.orglett.9b03702] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report that selective N-phosphorylation of aminoimidazoles results in a key steering element that controls isomeric selectivity in the condensation of β-ethoxy acrylamides and aminoimidazoles to furnish imidazo[1,2-a]pyrimidines. We identified conditions that provide highly selective (99:1) phosphorylation at the endo- or exocyclic nitrogen. Either the 2-amino or 4-amino isomer of the (benzo)imidazo[1,2-a]pyrimidine products could be isolated in 64-95% yield. Mass spectrometric analysis and computational studies give insight into the mechanism of this exceptionally selective transformation.
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Affiliation(s)
- Nicholas A White
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Kyle Clagg
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Lauren E Sirois
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Kyle A Mack
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Mohammad A Al-Sayah
- Department of Small Molecule Analytical Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - William A Nack
- Exemplify BioPharma , 3000 Eastpark Boulevard, Suite 500-A , Cranbury , New Jersey 08512 , United States
| | - Paul D O'Shea
- Exemplify BioPharma , 3000 Eastpark Boulevard, Suite 500-A , Cranbury , New Jersey 08512 , United States
| | - Haiming Zhang
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Francis Gosselin
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
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Nack WA, Wang X, Wang B, He G, Chen G. Palladium-catalyzed picolinamide-directed iodination of remote ortho-C-H bonds of arenes: Synthesis of tetrahydroquinolines. Beilstein J Org Chem 2016; 12:1243-9. [PMID: 27559375 PMCID: PMC4979757 DOI: 10.3762/bjoc.12.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/05/2016] [Indexed: 11/25/2022] Open
Abstract
A new palladium-catalyzed picolinamide (PA)-directed ortho-iodination reaction of ε-C(sp2)−H bonds of γ-arylpropylamine substrates is reported. This reaction proceeds selectively with a variety of γ-arylpropylamines bearing strongly electron-donating or withdrawing substituents, complementing our previously reported PA-directed electrophilic aromatic substitution approach to this transformation. As demonstrated herein, a three step sequence of Pd-catalyzed γ-C(sp3)−H arylation, Pd-catalyzed ε-C(sp2)−H iodination, and Cu-catalyzed C−N cyclization enables a streamlined synthesis of tetrahydroquinolines bearing diverse substitution patterns.
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Affiliation(s)
- William A Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Xinmou Wang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
| | - Bo Wang
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States; State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China
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4
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He G, Wang B, Nack WA, Chen G. Syntheses and Transformations of α-Amino Acids via Palladium-Catalyzed Auxiliary-Directed sp(3) C-H Functionalization. Acc Chem Res 2016; 49:635-45. [PMID: 27015079 DOI: 10.1021/acs.accounts.6b00022] [Citation(s) in RCA: 395] [Impact Index Per Article: 49.4] [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
α-Amino acids (αAA) are one of the most useful chiral building blocks for synthesis. There are numerous general strategies that have commonly been used for αAA synthesis, many of which employ de novo synthesis focused on enantioselective bond construction around the Cα center and others that consider conversion of existing αAA precursors carrying suitable functional groups on side chains (e.g., serine and aspartic acid). Despite significant advances in synthetic methodology, the efficient synthesis of enantiopure αAAs carrying complex side chains, as seen in numerous peptide natural products, remains challenging. Complementary to these "conventional" strategies, a strategy based on the selective functionalization of side chain C-H bonds, particularly sp(3) hybridized C-H bonds, of various readily available αAA precursors may provide a more straightforward and broadly applicable means for the synthesis and transformation of αAAs. However, many hurdles related to the low reactivity of C(sp(3))-H bonds and the difficulty of controlling selectivity must be overcome to realize the potential of C-H functionalization chemistry in this synthetic application. Over the past few years, we have carried out a systematic investigation of palladium-catalyzed bidentate auxiliary-directed C-H functionalization reactions for αAA substrates. Our strategies utilize two different types of amide-linked auxiliary groups, attached at the N or C terminus of αAA substrates, to exert complementary regio- and stereocontrol on C-H functionalization reactions through palladacycle intermediates. A variety of αAA precursors can undergo multiple modes of C(sp(3))-H functionalization, including arylation, alkenylation, alkynylation, alkylation, alkoxylation, and intramolecular aminations, at the β, γ, and even δ positions to form new αAA products with diverse structures. In addition to transforming αAAs at previously unreachable positions, these palladium-catalyzed C-H functionalization strategies enable new retrosynthetic logic for the synthesis of many basic αAAs from a common alanine precursor. This approach reduces the synthetic difficulty for many αAAs by bypassing the requirement for stereocontrol at Cα and relies on straightforward and convergent single-bond coupling transformations at the β-methyl position of alanine to access a wide range of β-monosubstituted αAAs. Moreover, these β-monosubstituted αAAs can undergo further C-H functionalization at the β-methylene position to generate various β-branched αAAs in a stereoselective and programmable fashion. These new strategies offer readily applicable methods for synthesis of challenging αAAs and may facilitate the efficient total synthesis of complex peptide natural products.
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Affiliation(s)
- Gang He
- State
Key Laboratory and Institute of Elemento-Organic Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Bo Wang
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William A. Nack
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- State
Key Laboratory and Institute of Elemento-Organic Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, China
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Zhang SY, Li Q, He G, Nack WA, Chen G. Pd-Catalyzed Monoselective ortho-C–H Alkylation of N-Quinolyl Benzamides: Evidence for Stereoretentive Coupling of Secondary Alkyl Iodides. J Am Chem Soc 2014; 137:531-9. [DOI: 10.1021/ja511557h] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Qiong Li
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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6
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He G, Zhang SY, Nack WA, Pearson R, Rabb-Lynch J, Chen G. Total Synthesis of Hibispeptin A via Pd-Catalyzed C(sp3)–H Arylation with Sterically Hindered Aryl Iodides. Org Lett 2014; 16:6488-91. [DOI: 10.1021/ol503347d] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ryan Pearson
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Javon Rabb-Lynch
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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7
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Wang B, Lu C, Zhang SY, He G, Nack WA, Chen G. Palladium-Catalyzed Stereoretentive Olefination of Unactivated C(sp3)–H Bonds with Vinyl Iodides at Room Temperature: Synthesis of β-Vinyl α-Amino Acids. Org Lett 2014; 16:6260-3. [DOI: 10.1021/ol503248f] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Bo Wang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chengxi Lu
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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8
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Lu C, Zhang SY, He G, Nack WA, Chen G. Palladium-catalyzed picolinamide-directed halogenation of ortho C–H bonds of benzylamine substrates. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.02.070] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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9
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Wang B, Nack WA, He G, Zhang SY, Chen G. Palladium-catalyzed trifluoroacetate-promoted mono-arylation of the β-methyl group of alanine at room temperature: synthesis of β-arylated α-amino acids through sequential C–H functionalization. Chem Sci 2014. [DOI: 10.1039/c4sc01545b] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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10
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Li Q, Zhang S, He G, Nack WA, Chen G. Palladium‐Catalyzed Picolinamide‐Directed Acetoxylation of Unactivated γ‐C(
sp
3
)H Bonds of Alkylamines. Adv Synth Catal 2014. [DOI: 10.1002/adsc.201400121] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Qiong Li
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Fax: (+1)‐814‐863‐5319
| | - Shu‐Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Fax: (+1)‐814‐863‐5319
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Fax: (+1)‐814‐863‐5319
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Fax: (+1)‐814‐863‐5319
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA, Fax: (+1)‐814‐863‐5319
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11
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Li Q, Zhang SY, He G, Ai Z, Nack WA, Chen G. Copper-catalyzed carboxamide-directed ortho amination of anilines with alkylamines at room temperature. Org Lett 2014; 16:1764-7. [PMID: 24588126 DOI: 10.1021/ol500464x] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [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
In this report, a highly efficient method for the room temperature installation of alkyl amino motifs onto the ortho position of anilines via Cu-catalyzed carboxamide-directed amination with alkylamines is described. This method offers a practical solution for the rapid synthesis of complex arylamines from simple starting materials and enables new planning strategies for the construction of arylamine-containing pharmacophores. A single electron transfer (SET)-mediated mechanism is proposed.
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Affiliation(s)
- Qiong Li
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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12
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He G, Zhang SY, Nack WA, Li Q, Chen G. Use of a Readily Removable Auxiliary Group for the Synthesis of Pyrrolidones by the Palladium-Catalyzed Intramolecular Amination of Unactivated γ C(sp3)H Bonds. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305615] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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He G, Zhang SY, Nack WA, Li Q, Chen G. Use of a Readily Removable Auxiliary Group for the Synthesis of Pyrrolidones by the Palladium-Catalyzed Intramolecular Amination of Unactivated γ C(sp3)H Bonds. Angew Chem Int Ed Engl 2013; 52:11124-8. [DOI: 10.1002/anie.201305615] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Indexed: 01/19/2023]
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Zhang SY, Li Q, He G, Nack WA, Chen G. Stereoselective Synthesis of β-Alkylated α-Amino Acids via Palladium-Catalyzed Alkylation of Unactivated Methylene C(sp3)–H Bonds with Primary Alkyl Halides. J Am Chem Soc 2013; 135:12135-41. [DOI: 10.1021/ja406484v] [Citation(s) in RCA: 291] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
United States
| | - Qiong Li
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
United States
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
United States
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
United States
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15
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Nack WA, He G, Zhang SY, Lu C, Chen G. Iodination of Remote Ortho-C–H Bonds of Arenes via Directed SEAr: A Streamlined Synthesis of Tetrahydroquinolines. Org Lett 2013; 15:3440-3. [DOI: 10.1021/ol4015078] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chengxi Lu
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Zhang SY, He G, Nack WA, Zhao Y, Li Q, Chen G. Palladium-catalyzed picolinamide-directed alkylation of unactivated C(sp3)-H bonds with alkyl iodides. J Am Chem Soc 2013; 135:2124-7. [PMID: 23350845 DOI: 10.1021/ja312277g] [Citation(s) in RCA: 328] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report an efficient method for the alkylation of γ-C(sp(3))-H bonds of picolinamide-protected aliphatic amine substrates with primary alkyl iodides via palladium catalysis. Ag(2)CO(3) and dibenzyl phosphate, (BnO)(2)PO(2)H, are critical promoters of this reaction. These reactions provide a convenient and straightforward method for the preparation of high-value N-containing products from readily available amine and alkyl iodide precursors.
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Affiliation(s)
- Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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He G, Lu C, Zhao Y, Nack WA, Chen G. Improved Protocol for Indoline Synthesis via Palladium-Catalyzed Intramolecular C(sp2)–H Amination. Org Lett 2012; 14:2944-7. [DOI: 10.1021/ol301352v] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Chengxi Lu
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yingsheng Zhao
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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18
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Zhao Y, He G, Nack WA, Chen G. Palladium-Catalyzed Alkenylation and Alkynylation of ortho-C(sp2)–H Bonds of Benzylamine Picolinamides. Org Lett 2012; 14:2948-51. [DOI: 10.1021/ol301214u] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Yingsheng Zhao
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gang He
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - William A. Nack
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gong Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Zhang SY, He G, Zhao Y, Wright K, Nack WA, Chen G. Efficient alkyl ether synthesis via palladium-catalyzed, picolinamide-directed alkoxylation of unactivated C(sp3)-H and C(sp2)-H bonds at remote positions. J Am Chem Soc 2012; 134:7313-6. [PMID: 22486219 DOI: 10.1021/ja3023972] [Citation(s) in RCA: 296] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We report the efficient synthesis of alkyl ethers by the functionalization of unactivated sp(3)- and sp(2)-hybridized C-H bonds. In the Pd(OAc)(2)-catalyzed, PhI(OAc)(2)-mediated reaction system, picolinamide-protected amine substrates undergo facile alkoxylation at the γ or δ positions with a range of alcohols, including t-BuOH, to give alkoxylated products. This method features a relatively broad substrate scope for amines and alcohols, inexpensive reagents, and convenient operating conditions. This method highlights the emerging value of unactivated C-H bonds, particularly the C(sp(3))-H bond of methyl groups, as functional groups in organic synthesis.
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Affiliation(s)
- Shu-Yu Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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