Benzyl xanthate photolysis

In the thiohydroxamate method, activated acceptors are required for successful addition reactions because the thiohydroxamate is relatively reactive towards alkyl radicals. An ingenious method to circumvent this problem has recently been communicated by Zard.160 Photolysis of benzyl xanthate (40) with a UV lamp in the presence of N-methylmaleimide (NMM) provided the adduct (41) in 40% yield, as illustrated in Scheme 50. In this reaction, the competition reaction between the desired addition to the acceptor and the addition to the precursor still exists. However, addition to the precursor is reversible and,... 

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