One-Step Synthesis of Triethynylvinylmethanes and Tetraethynylmethanes by GaCI_3-Promoted Diethynylation of 1,4-Enynes and 1,4-Diynes

摘要

Polyethynylmethanes are an interesting group of compounds,which have attracted much attention,particularly in relation to the development of high-carbon-content materials and to the construction of nanostructures.Triethynylcarbinols readily available by the acetylide addition to carbonyl compounds have often been employed for these purposes.Triethynylvinylmethanes and tetraethynylmethanes possessing a fully functionalized quaternary carbon atom,however,were not known until Feldman prepared them in 1993.They were synthesized in a stepwise manner employing the Claisen rearrangement as a key step to construct the quaternary carbon atom.