Spiro-oxetanes, synthesis

A very promising new method for converting oxiranes, as well as ketones, into oxetanes has recently been reported. This method uses the carbanion of dimethyl(N-tosyl)sulfoximine and gave good yields in the several cases reported. When this reagent is employed with ketones, oxirane formation is presumably an intermediate stage, but the oxirane is not isolated. The method thus provides an excellent synthesis of spiro-oxetanes from ketones, as the example with camphor in equation (85) shows (79JA6135). 

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