Stereoselectivity of Addition to Alkenes

A potential method for the preparation of novel amino acids via the highly selective addition of radicals to the glyoxylic oxime derivative of Oppolzer s camphor sultam (88) has been reported. Both Lewis acid and non-Lewis acid-mediated reaction conditions for the addition of alkyl radicals generated from alkyl iodides and Et3B/Bu3SnH were examined. A new chiral auxiliary based upon (R,/ )-2,5-diphenylpyrrolidine has been used in the addition of phenylthiyl radicals to unsaturated methacrylamides. The selectivity was found to be better than that reported for the stmcturally related 2,5-dimethylpyrrolidine derivative.  

An investigation into the stereoselectivity of addition of radicals to cinnamyl-4-phenyloxazolidine-2-ones has shown that the regioselectivity of the process was dependent upon at least three factors, including the stability of the adduct radical. 

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