Synthesis of enantiopure (R,R)- and (S,S)-cis-2,3-propanoprolines
摘要:
A novel approach to the synthesis of an enantiopure bicyclic proline analogue, hexahydrocyclopentalb]pyrrole-6a(1H)-carboxylic acid ('2,3-propanoproline'), has been developed. The method relied on tandem Strecker-nucleophilic cyclization reaction of 2-(2-bromoethyl)cyclopentanone. The overall synthetic scheme included six steps and resulted in 18% overall yield of both enantiomers of the title amino acid. (C) 2010 Elsevier Ltd. All rights reserved.
Diastereoselective Intramolecular Additions of Allyl- and Propargylsilanes to Iminium Ions: Synthesis of Cyclic and Bicyclic Quaternary Amino Acids
作者:Santos Fustero、Natalia Mateu、Antonio Simón-Fuentes、José Luis Aceña
DOI:10.1021/ol1010246
日期:2010.7.2
Chiral imino lactones derived from (R)-phenylglycinol containing an allyl- or propargyltrimethylsilyl group in the side chain readily cyclized in the presence of acidic reagents to afford spirocyclic compounds with high diastereoselectivity. Removal of the chiral auxiliary produced 2-substituted 1-aminocycloalkanecarboxylic acids, whereas further cyclizations by means of metathesis or hydroamination reactions led to bicyclic derivatives of pipecolic acid and proline.