Beta-amino acids to piperidinones by Petasis methylenation and acid-induced cyclization.

Ester-imine derivatives of beta-amino acids were methylenated with dimethyltitanocene under microwave irradiation and the resulting enol ethers cyclized with Brönsted acid or triisopropylaluminium to give 2,6-syn-disubstituted piperidinones in good yield and diastereoselectivity. The method is analogous to the Petasis-Ferrier rearrangement of 1,3-dioxan-4… CONTINUE READING