Homologation of Four-Membered Heterocycles

Cohen and Mudryk reported in 1989 for the first time the reductive opening of oxetanes (89JOC5657). Thus, treatment of oxetanes 2 with lithium and a stoichiometric 

The above shown methodology has found wide application in organic synthesis. For instance, the reaction of intermediates (18) with carbonyl compounds gives 1,4-diols that undergo cyclization leading to tetrahydrofurans (20) under acidic conditions (Table 1). 

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