Dioxolanones as synthetic intermediates. Part 1. Synthesis of α-keto acids, α-keto aldehydes, and α-ketols

Abstract

2,2-Pentamethylene-1,3-dioxolan-4-one[cyclohexanespiro-2′-(1′,3′-dioxolan)-4′-one](10) has been elaborated to provide 5′-ylidene derivatives using a Wittig approach. This apparently novel class of compounds is subject to nucleophilic attack at the 4-position because of strain inherent in the 5-membered ring. Thus alkaline hydrolysis leads to the formation of α-keto acids; hydride reduction of dioxolanones incorporating conjugated aryl substituents using di-isobutylalurninium hydride leads to α-keto-aldehydes; the reaction of dioxolanone (15) with methylmagnesium iodide gave the α-ketol (40).