REACTIONS OF SUBSTITUTED (2-BUTENE-1,4-DIYL)MAGNESIUM COMPLEXES WITH CARBOXYLIC ESTERS AND LACTONES - FORMATION OF A VERSATILE INTERMEDIATECAPABLE OF GENERATING SUBSTITUTED CYCLOPENTENOLS, FUSED-RING CYCLOPENTENOLS, OR BETA,GAMMA-UNSATURATED KETONES

Reaction of the magnesium complexes of substituted 1,3-dienes with eit her carboxylic esters or lactones at low temperature (-78 to -10 degre es C) generates the magnesium salt of a cyclopropanol (4). This interm ediate can either be trapped as an acetate of the cyclopropanol (9) or it can be heated to yield substituted cyclopentenols. Moreover, when this intermediate is protonated, it undergoes an intramolecular rearra ngement to yield beta,gamma-unsaturated ketones. Accordingly, this pro tocol allows the generation of a wide range of complex molecules from a single intermediate in high isolated yields.