Bifunctional conjunctive reagents

TMMfrom Bifunctional Conjunctive Reagents 3.23.2.1 Cycloaddition with the parent system... 

Bifunctional conjunctive reagents (BCRs), such as a 1,3-substituted 2-methylenepropane (96), can serve as effective TMM synthons via transition metal catalysis. In this case, the transition metal complex can promote the elimination of the elements X—Y from (96) to form a coordinated TMM species. Cycli-zation of this intermediate with an alkene thus produces the methylenecyclopropane product and also regenerates the catalyst (Scheme 3). In the last decade a number of BCRs utilizing this concept, or some modifications thereof, has been developed for various TMM synthons. ... 

Acetoxymethyl-3-allyltrimethylsilane is a bifunctional or conjunctive reagent that provides an efficient and versatile means of synthesizing methylenecyclopentanes via [3 + 2] cy-cloaddition18 In the presence of catalytic amounts of an appropriate palladium(O) complex, the combination of the allyl acetate and allylsilane functionalities results in the formation of a metal-stabilized trimethylenemethane unit (TMM-Pd). This is able to undergo Smooth [3 + 2] cyeloaddition reactions with electron-deficient olefins. 

Introduction. The title aUylsilane reagent has been enployed as a conjunctive reagent which is considered to be a synthetic equivalent of a zwitterionic, bifunctional compound possessing a nucleophilic allylic anion synthon and an electrophilic cation synthon in the same molecule (1). 

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