Synthesis of gem-difluoromethylenated analogues of boronolide

Abstract

The straightforward synthesis of four gem-difluoromethylenated analogues 4–7 of boronolide is described. The key steps of the synthesis include the concise preparation of the key intermediates 12a–b through the indium-mediated gem-difluoropropargylation of aldehyde 9 with the fluorine-containing building block 11 and the efficient construction of α,β-unsaturated-δ-lactones 15a–b via BAIB/TEMPO-procedure.

Keywords

• boronolide
• gem-difluoromethylenated analogues
• gem-difluoropropargylation
• α,β-unsaturated-δ-lactones