Oxetanes synthesis Paterno-Biichi reaction

The Paterno-Biichi reaction has been employed in the synthesis, often in high yield, of a large variety of substituted oxetanes. In addition to simple aliphatic and aromatic alkenes, cycloaddition of ketones to, for example, fumaronitrile,284 l,3-diacetylimidazolin-2-one288 [Eq. (73)], and allenes286 has been reported. Allenes yield both 1,5- and l,6-dioxaspiro[3.3]heptanes as well as the 2-alkylidene-oxetane this is illustrated for benzophenone and tetramethylallene in Eq. (74). Cycloaddition of ketones to ketenimines to form 2- and... 

The cleavage of oxetans formed in the Paterno-Biichi reaction has also been used with effect.Thus an extremely simple and efficient synthesis of D,L-apiose (53) involved the base-induced cleavage of the oxetan (52), derived from diacetoxyacetone and vinylene carbonate (Scheme 15). A reductive cleavage of... 

Morris, T. H., Smith, E. H., and Walsh, R., Oxetane synthesis methyl vinyl sulphides as new traps of excited benzophenone in a stereoselective and regiospecific Paterno-Biichi reaction, J. Chem. Soc., Chem. Commun., 964, 1987. 

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