SELECTIVE REDUCTIONS .13. REACTION OF DELTA2-CYCLOPENTENONES WITH REPRESENTATIVE COMPLEX HYDRIDES . ALUMINUM HYDRIDE AS A SELECTIVE REAGENT FOR REDUCTION OF CARBONYL GROUP IN DELTA2-CYCLOPENTENONES

The reduction of 2-cyclopenten-1-one and 5,6-dihydro-erado-dicyclopentadien-1-one with metal hydrides takes place with considerable concomitant saturation of the double bond. However, the inverse addition of 0.667 mole equiv of aluminum hydride to 2-cyclopenten-1-one, 3-substituted 2-cyclopenten-1-ones, 5,6-dihydro-endo-dicyclopentadien-1-one, and 3-substituted 5,6-dihydro-endo-dicyclopentadien-1-ones, produces the unsaturated carbinols in satisfactory purity and yield and thus provides an effective route for the selective reduction of the carbonyl group in ∆2-cyclopentenones. © 1969, American Chemical Society. All rights reserved.