ChemInform Abstract: Preparation of Cyclobutyl Group Carrying Cyclobutanones and Related Synthetic Building Blocks.

Abstract

Preparation of Cyclobutyl Group Carrying Cyclobutanones and Related Synthetic Building Blocks.-Unsymmetrically substituted cyclobutyl-cyclobutanes are prepared via vinylcyclobutanes. Two methods are applied. The first method starts with (V) and involves Grignard addition, protection of the hydroxy group, cycloaddition of dichloroketene (II) followed by a reducing step to give a mixture of diastereomers (VII). A second Grignard reaction can introduce a further aryl residue. The second sequence ((XI)→(XV)) involves two methylene Wittig reactions and a dichloroketene cycloaddition. The starting compound (V) is obtained by cycloaddition of dichloroketene (II) to diene (I) after reduction of monoadduct (III). Bisadduct (IV) is new to the literature.