Tertiary Phosphine-triggered Cascade/Annulation Reactions Of MBH Derivatives Or Allenoate

Nucleophilic phosphine catalysis has proven to be a powerful tool for the synthesis of cyclic and heterocyclic compounds. Owing to their comparatively strong and readily tunable nucleophilicity, phosphines can be easily tailored to efficient reactions with control over reaction selectivity. Generally, tertiary phosphine-triggered annulation occurred via nucleophilic addition of phosphines to activated olefins, allenes and alkylnes. The resultant zwitterionic intermediates react with electrophiles to yield cyclic compounds.First of all, we summarize the recent achievements in the area of nucleophilic phosphine catalysis in the first chapter.Secondly, a phosphine-catalyzed domino reaction might be suspended or prevented when competitive reactios occur, such as behaves of phosphonium ylides do in the Wittig reaction. Thus, subtle tuning of the catalysis process is a significant project. And only a few successful attempts have been performed on the tunable phosphine-triggered domino reactions. In this paper, we report the tunable phosphine-triggered cascade reactions of MBH derivatives and 3-acyl-2H-chromenones:highly selective synthesis of potential biologically active 2,3-dihydrofuran-fused chromen-2-ones, and 4-allyl-3-acyl-chromen-2-ones, and 6H-benzo[c]chromen-6-ones. This method has the advantages of mild conditions, simple workup, and wide substrate scope, which make it powerful for the synthesis of diverse chromenones. The biological activities of 17 comprounds have been tested. Moreover, the tunable phosphine-triggered highly selective cascade reactions have given new insights into catalytic selective synthesis.In addition, we developed a novel bicylization reaction of allenoate and 1, 4-enediones:for the effective synthesis of 3a,6a-dihydrofuro[2,3-b]furans derivative.