Bisketenes, silylated

In a novel method of forming cyclobutanols, titanium(IV) chloride is found to promote the condensation of substituted bisketene silyl acetals 23 with more reactive carbon electrophiles such as acetic anhydride or benzoic anhydride. In each experiment, it is apparent that only one diastercomer of the substituted 2,4-dicarbomethoxycyclobutanols 24 is furnished, as can be vindicated by NMR spectral analysis.33... 

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