Phosphine-Catalyzed Reactions of Activated Olefins Tethered to Cycloalkanones. Substrate- and Solvent-Controlled Synthesis of Bicyclo[3.2.1]octanones, Mixed Acetals, and Morita-Baylis-Hillman Products

The n-Bu3P organocatalyzed reaction of cycloalkanones, i.e., cyclopentanones or 1,3-cyclopentanediones tethered to actived olefins, afforded selectively and in high yields three different types of products: bicyclo[3.2.1]octanones, mixed acetals, and Morita-Baylis-Hillman products. The progress of the reaction was closely related to the reaction medium and to the length of the tether located between the cyclopentanone (-dione) and the activated olefin.