Nogami H, Kanai M, Shibasaki M. Application of the Lewis acid-Lewis base bifunctional asymmetric catalysts to pharmaceutical syntheses: stereoselective chiral building block syntheses of human immunodeficiency virus (HIV) protease inhibitor and beta3-adenergic receptor agonist.
Chem Pharm Bull (Tokyo) 2003;
51:702-9. [PMID:
12808250 DOI:
10.1248/cpb.51.702]
[Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chiral building block syntheses of promising drugs were achieved using two types of catalytic stereoselective cyanosilylations of aldehydes promoted by Lewis acid-Lewis base bifunctional catalysts 1 and 2 as the key steps (diastereoselective cyanosilylation of amino aldehyde and enantioselective cyanosilylation). In the first part of this article, syntheses of chiral building blocks (6) of Atazanavir (3: human immunodeficiency virus (HIV) protease inhibitor) using the bifunctional catalyst 2 are discussed. The reaction of Boc-protected phenylalaninal 21 in the presence of 1 mol% catalyst 2 selectively afforded the anti isomer 22 as the major product (diastereomeric ratio=97 : 3), which was successively converted to the corresponding epoxide 6 in six steps. In the second part, we describe a chiral building block synthesis of beta(3)-adrenergic receptor agonists. The enantioselective cyanosilylation of 3-chlorobenzaldehyde (38) with 9 mol% catalyst 1 gave the chiral cyanohydrin 39, which was converted to beta-hydroxyethylamine 40 by reduction. Moreover, the chiral ligand of catalyst 1 could be recovered without column chromatography and reused without decreasing its activity.
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