Cyclobutane serine amino acid derivatives as 5-hydroxyproline precursors

Abstract

The synthesis of the 5-hydroxyproline derivatives 3a and 3b using cyclobutane serine analogs 1 and 2 as starting materials is reported. This process occurs with moderate cis/trans selectivity. A mechanism for this reaction is also proposed. Cyclobutane serine analog 1 was tested in tandem Michael and Wittig-like reactions, providing some evidence of the mechanism proposed.