An efficient route to 3-substituted cyclobutanone derivatives

An efficient route to 3-(hydroxymethyl)cyclobutanone acetals via a [2+2] cycloaddition reaction is reported. The dramatic effect of different diol acetals on benzyl deprotection is discussed. Efficient synthesis of two synthetically useful intermediates, 3-methylenecyclobutanone acetal and 3-(bromomethyl)cyclobutanone, are provided.