2-Acetoxymethyl-3-allyltrimethylsilane

Methylenecyclopentanes. 2-Acetoxymethyl-3-allyltrimethylsilane (1) adds to a variety of electron-deficient alkenes in the presence of catalytic amounts of tetrakis(triphenylphosphine)palladium(0) and l,2-bis(diphenylphosphino)ethane to afford methylenecyclopentanes. The allylsilane 1 is prepared in four steps from methallyl alcohol. 

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. 

The palladium-catalyzed [3+2] cycloaddition reaction between enantiomerically pure a,P-unsaturated sulfoxides and trimethylenemethane (266), using the methodology developed by Trost [198], has been reported [199]. Thus, reaction of the sulfoxide (31), 2-acetoxymethyl-3-allyltrimethylsilane (2eq), palladium acetate (5mol%), and triisopropylphosphite (20 eq) in THF under reflux gave the major cycloadduct (267) in 80% yield and 80% de (Scheme 5.87). Moderate to good levels of asymmetric induction were observed for various a,P unsaturated sulfoxides. 

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