A flexible approach to (S)-5-alkyl tetramic acid derivatives: application to the asymmetric synthesis of (+)-preussin and protected (3S,4S)-AHPPA.
[reaction: see text] A flexible asymmetric approach to 5-alkyl tetramic acid derivatives is described, which is based on the use of 9 as the first synthetic equivalent to chiral nonracemic tetramic acid 5-carbanionic synthon 9b. The existence of the carbanion intermediate 9b was proven by trapping with trimethylchlorosilane. Application of the present method to the synthesis of antifungal alkaloid (+)-preussin, as well as protected (3S,4S)-AHPPA 6, is also described.
Huang
Pei-Qiang
PQ
Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, Xiamen, Fujian 361005, P. R. China. pqhuang@xmu.edu.cn
Wu
Tian-Jun
TJ
Ruan
Yuan-Ping
YP