Asymmetric synthesis of β-substituted δ-ketoesters via michael-additions of samp/ramp-hydrazones to α,β-unsaturated esters, virtually complete 1.6-asymmetric induction

✍ Scribed by Dieter Enders; Kyriakos Papadopoulos

• Book ID: 104250276
• Publisher: Elsevier Science
• Year: 1983
• Tongue: French
• Weight: 248 KB
• Volume: 24
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)99823-5

✦ Synopsis

A simple and efficient X-step asymmetric synthesis of 6-substituted 6-ketoesters 2 in 45-62% overall chemical yield and Z96--100% ee is described.

The key step is an asymmetric Michael-addition of lithiated methylketone-SAMPor RAMP-hydrazones to a,B-unsaturated esters 2 with virtually complete 1.6-asymmetric induction.