Construction of Fully Substituted Cyclobutanes by Tandem Reaction of 1,4-Diyn-3-ols and Anhydrides.

A concise and efficient synthesis of fully substituted cyclobutane derivatives from 1,4-diyn-3-ols and anhydrides was developed. Mechanistic studies indicated that a tandem esterification, isomerization to give allenyl ester, and homointermolecular [2+2] cycloaddition might be involved. The features of this protocol are its operational practicality, mild reaction conditions, and high regio- and stereoselectivity, and it is a readily accessible gram-scale synthesis.