Asymmetric electrophilic methoxyselenenylations and cyclizations with 3-camphorseleno derivatives

A series of novel 3-camphor-based diselenides, differing in substitution at C-2, was prepared. The corresponding allyl selenides were used as protecti ng groups for the diselenide moieties in several subsequent transformations . The diastereoselective methoxyselenenylation of alkenes was achieved with methanolic selenenyl triflates derived from the camphor diselenides, of wh ich the 2-keto analogue proved the most effective. Diastereoselective elect rophilic cyclizations of unsaturated alcohols, carboxylic acids and amides were most effectively performed with the corresponding selenenyl chloride, containing a spiro-oxazolidinone moiety at C-2 of the camphor residue. The absolute configurations of several products were determined by reductive de selenization. (C) 1999 Elsevier Science Ltd. All rights reserved.