The search for tolerant Lewis acid catalysts.: Part 1: Chiral silicon Lewis acids derived from (−)-myrtenal

✍ Scribed by Benoit Mathieu; Laurence de Fays; Léon Ghosez

• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 70 KB
• Volume: 41
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)01694-4

✦ Synopsis

We have shown that association of a bulky silicon group with the bis(trifluoromethanesulfonyl)imide leaving group unexpectedly enhances the electrophilic character of the R 3 SiNTf 2 silylating agent. The presence of a chiral substituent derived from (-)-myrtenal on the silicon atom led to a Lewis acid, which efficiently catalyzes the Diels-Alder reaction of a,b-unsaturated esters.

Although not yet preparatively useful, the enantiomeric excesses (up to 54%) were the highest ever reported for a chiral silicon Lewis acid.