We commenced preliminary optimization of the reaction conditions for the envisioned Cfunctionalization with several silylated model substrates derived from protected and unprotected, α-and β-, gluco-and galacto-configured pyranosides (e.g., substrate 2a, Fig. , see the Supplementary Information for details). Under the typical conditions used in Giese-type photoredox-mediated Ccouplings with alkyl halides, 41 all substrates displayed formation of the C4-functionalized products with methyl acrylate somophile (e.g., product 3a), while no detectable side-products from functionalization of the other positions in the carbohydrate skeleton were observed. Nevertheless, considerable amounts of side-products were formed due to the reductive dehalogenation of the substrate (e.g., side-product 4a) and premature addition of the somophile to α-silyl C-radical intermediate (e.g., side-product 5a).