Unique Divergent Reactivity of Boc-Protected Homopropargylic Alkoxyalkylamines in the Gold(I)-Catalyzed Domino Catalytic Reactions: Application to the Formal Synthesis of (-)-Pseudodistomin B

Abstract

By using t-Boc-protected homopropargylic alkoxyalkylamines as substrates, the reactivity between the carboxylation-promoted and the alkoxylation-promoted domino processes in the gold-catalyzed reaction was systematically compared. Interestingly, the result varies significantly depending upon the structure of the alkynes and the nature of the phosphine ligands. The alkoxylation-induced pathway represents a new synthetic method towards 2,4,5-trisubstituted piperidines. A formal synthesis of (-)-pseudodistomin B based upon this interesting chemoselectivity was accomplished.