Synlett

Enantioselective desymmetrization of tropinone derivatives by hydroboration

N Cramer, S Laschat, A Baro, W Frey

Index: Cramer, Nicolai; Laschat, Sabine; Baro, Angelika; Frey, Wolfgang Synlett, 2003 , # 14 p. 2175 - 2177

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Citation Number: 13

Abstract

Abstract N-Protected tropenone derivatives 3, prepared from the respective pyrroles 5 and tetrabromoacetone (6), were used as starting materials for desymmetrization by hydroboration of the CC double bond. Hydroboration of 3a with (-)-(Ipc) 2 BH followed by oxidation, however, gave the desired 6-hydroxylated product 4a only in low yield due to byproduct formation. After acetalization of the carbonyl group in 3, the corresponding ...