InCl3-induced C-glycosylation of per-O-acetylglycals with allyltrimethylsilane

InCl3 has been used for the first time as a mediator for the C-glycosylatio n of per-O-acetylglycals with allyltrimethylsilane, and the reactions proce eded to give products in good-to-excellent yield and in high diastereoselec tivity. The 1,5-anti diastereoselectivity in the allylation of 3,4,6-tri-O- acetyl-1,5-anhydro-2-deoxy-D-arabino-hex-1-enitol and 3,4-di-O-acetyl-1,5-a nhydro-2,6-dideoxy-L-arabino-hex-1-enitol and the 1,4-anti diastereoselecti vity with 3,4-di-O-acetyl-1,5-anhydro-2-deoxy-D-erythro-pent-1-enitol are i n the range 80-90%, whereas 3,4,6-tri-O-acetyl-1,5-anhydro-2-deoxy-D-lyxo-h ex-1-enitol furnished exclusively the corresponding C-alpha-D-galactopyrano syl compound. (C) 1999 Elsevier Science Ltd. All rights reserved.