Intra-and Intermolecular Trapping Reactions of Benzynes Generated by Hexadehydro-Diels-Alder Reaction

摘要

Benzynes are useful building blocks and intermediates in synthetic organic chemistry because of their high reactivity.In particular,the bent and strained triple bond in benzyne is a highly reactive site,so that stress can be released to revert to the benzene form.Hence,organic chemists have used this versatile intermediate in various reactions to access complex natural products.The traditional methods2 for generating benzyne involve the elimination of two adjacent substituents by the action of a strong base or fluoride source and subsequent trapping of the benzynes by diverse A-B such as alcohols and amines(Scheme 1(a)).Recently,a hexadehydro-Diels-Alder reaction(HDDA)utilizing triynes was developed and utilized for intra-and intermolecular trapping reaction(Scheme 1(b)).