Studies on the generation and the reactivity of alkylidene carbenes from alkynyliodonium salts

Abstract

Studies aimed at the alkylidene carbenes generated from alkynyliodonium salts and synthesis of nearly fused tricyclopentanoid (triquinane structure) have been performed. As preliminary studies, generation and reactivity of alkylidene carbenes from alkynyliodonium salts were studied. Their generation was highly dependent on the reaction conditions, alkyne``s substituents and counter anion attached to alkynyliodonium salts, and the nature of the nucleophiles. In this study, we investigated on the reactivity of alkylidene carbenes under various reaction conditions. In the synthesis of triquinanes, the key step of the sequence utilized a intramolecular diyl trapping reaction via cyclopropanation of alkylidene carbene. The cyclization reaction seemed that the moiety of nucleophiles played a significant role in the generation and reactivity of alkylidene carbenes. This tandem alkylidene carbene reaction and uses of polyvalent iodine would be applied to synthetic method of natural product in organic chemistry.