Cyclobutanes and cyclobutenes through [2+2] photocycloadditions to α,β-unsaturated γ-lactones

Cyclobutane and cyclobutene compounds are useful intermediates in organic synthesis. This review deals with the preparation of the bicyclo[3.2.0]heptan-2- one scaffold by the photochemical reaction of chiral 5-O-hydroxymethyl-2(5H)- furanone derivatives to alkenes, common and key step in the synthesis of (+)-grandisol, (+)-lineatin and cyclobutane nucleoside analogues.