Controllable methylenation with ethylene glycol as the methylene source: bridging enaminones and synthesis of tetrahydropyrimidines

Abstract

Controllable methylenation using renewable ethylene glycol as the methylene source has been developed for the introduction of one or two methylene building blocks in a single reaction. The bridging of enaminones and the synthesis of tetrahydropyrimidines proceeded smoothly with good yields, and bis-enaminones can be further converted into 1,4-dihydropyridines. The presented results shed light on a different usage of ethylene glycol and could inspire novel experimental design by using ethylene glycol as the methylene source.