The Synthesis of
Source: Advanced Synthesis & Catalysis, Volume 354, Number 17, 26 November 2012 , pp. 3311-3325(15)
Abstract:<title type="main">Abstract</title> (2S,3aR,7aS)-Perhydroindolic acid, the key intermediate in the synthesis of trandolapril, and its trans-isomers, were readily prepared. These proline-like molecules are unique in that they contain a rigid bicyclic structure, with two hydrogen atoms trans to each other at the bridgehead carbon atoms. These molecules were used successfully as chiral organocatalysts in asymmetric domino Michael addition/cyclization reactions of aldehyde esters with β,γ-unsaturated α-keto esters. They proved to have excellent catalytic behavior, allowing for the synthesis of multi-substituted, enantiomerically enriched hemiacetal esters. Under optimal conditions (using 10 mol% catalyst loading), a series of β,γ-unsaturated α-keto esters was examined with up to 99% de, ee and yield, respectively. Additionally, the enantiomerically enriched hemiacetal esters could be readily transformed into their corresponding bioactive pyrano[2,3-b]pyrans (possessing a multi-substituted bicyclic backbone).
Document Type: Research article
Affiliations: 1: School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China, phone: (+86)-21-5474-3265, Fax: (+86)-21-5474-3265 2: School of Pharmacy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
Publication date: 2012-11-26