Synthesis of Amathaspiramides by Aminocyanation of Enoates

摘要

Concise routes for the total and formal syntheses of the amathaspiramides were developed through a formal [3+2] cycloaddition between lithium(trimethylsilyl) diazomethane and alpha,beta-unsaturated esters. The effectiveness of this new cycloaddition for the construction of Delta(2)-pyrazolines containing a alpha-tert-alkylamino carbon center and subsequent facile protonolytic N-N bond cleavage allows the synthesis of a key intermediate of the amathaspiramides and other alpha,alpha-disubstituted amino acid derivatives.