Kt. Mead et R. Zemribo, STUDIES IN SPIROKETAL SYNTHESIS .1. NUCLEOPHILIC-ADDITION TO AN OXY-STABILIZED CARBONIUM-ION GENERATED ON A 1,7-DIOXASPIRO[5.5]UNDECANE RING-SYSTEM, Synlett, (11), 1996, pp. 1063
The low temperature reaction of 2-methoxy spiroketal 5 with a series o
f silane nucleophiles has been studied. The reaction was found to be L
ewis acid - dependent, and sensitive to changes in both solvent and si
lane reagent. When the nucleophile is carbon - based, the product of C
(2)-substitution is diastereomerically pure.