Radical reactions stereochemical induction

Complimentary to the use of glycosylfluorides is the ability to convert glycosylchlorides to C-glycosides under radical conditions. As shown in Scheme 5.2.6, Bednarski, et a/.,13 effected such reactions utilizing allyltributyltin and photolytic conditions. Although the modified sialic acid was isolated in 60% yield, no stereochemical induction was observed. 

For lead references see Yamamoto, Y. Maruyama, K. The Opposite Diastereoselectivity in Alkylation and Protonation of Enolates J. Chem. Soc., Chem. Commun. 1984, 904-905. Fleming, I. Lewis, J. J. A Paradigm for Diastereoselectivity in Electrophilic Attack on Trigonal Carbon Adjacent to a Chiral Center The Methylation and Protonation of Some Open-Chain Enolates J. Chem. Soc., Chem. Commun. 1985, 149-151. McGarvey, G. J. Williams, J. M. Stereoelectronic Controlling Features of Allylic Asymmetry. Application to Ester Enolate Alkylations J. Am. Chem. Soc. 1985, 107, 1435-1437. Hart, D. J. Krishnamurthy, R. Investigation of a Model for 1,2-Asymmetric Induction in Reactions of a-Carbalkoxy Radicals A Stereochemical Comparison of Reactions of a-Carbalkoxy Radicals and Ester Enolates J. Ors. Chem. 1993, 57, 4457-4470. 

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