The stereochemistry of the addition of titanium enolates of N-propionyl-oxazolidin-2-ones to 5- and 6-membered N-acyliminium ions
作者:Ronaldo A. Pilli、Conceição de Fátima Alves、Maria Alice Böckelmann、Yvonne P. Mascarenhas、J. Geraldo Nery、Ivo Vencato
DOI:10.1016/s0040-4039(99)00398-6
日期:1999.4
The stereochemistry of the addition of the N-propionyl titanium enolates 2a and 2b to 5- and 6-membered 2-ethoxycarbamates 1a-f was investigated. The addition proceeded stereoselectively to afford the corresponding (2S,1′S)-2-substituted pyrrolidines as the major diastereoisomer. Despite the lack of reactivity between 2-ethoxypiperidines 1b and N-propionyl titanium enolates 2a and 2b, less bulky carbamate