Stannoxanes as Covalent Templates

Shanzer and Mayer-Shochet have utilized disubstituted stannoxanes as covalent templates for the formation of tetralactones. In this procedure, a dialkyl stannoxane is condensed with a glycol to form a cyclic-distannoxane as illustrated below. In a typical preparation, the distannoxane (i) was dissolved in CCI4 (ca. 0.04 At) at reflux and sebacoyl chloride (2 eq) was added dropwise at reflux. After heating for 20 h, the solution was concentrated to a solid. Chromatography afforded the tetralactone in 30% yield.  

Although several examples are presented in this paper, the method is too new for much literature to have yet accumulated. 

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