Reaction of Phenylselenenyl Chloride with Δ^2-Erythrinans in Methanol : Conformational Fluctuation and Stereochemical Pathway

概要

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Reaction of Δ^2-erythrinan derivatives with PhSeCl in methanol gave the following results. The PhSe group was introduced from the β-face (convex face) for 6β-ethoxycarbonyl-7-oxo and Δ^6-7-mesyloxy derivatives (1 and 12), and from the α-face (concave face) for 7α- and 7β-mesyloxy derivatives (16 and 24), while the C-Se bond was always formed at C-3. The structure and stereochemistry of the products were proved by X-ray analyses of the derived 7-O-mesylates (5 and 17). The reasons for the above stereochemical difference and the regiochemical identity were explained by considering the conformational fluctuations in hte ground and transition states of the model compounds a, b, and c based on Chem 3D calculations. These results show that small conformational fluctuations can produce great changes in the stereochemical outcome, particularly in ionic addition reactions.
社団法人日本薬学会の論文
1992-01-25