Ferrier Rearrangement of 1,2-Dihydropyrans with Organozinc Species in Toluene/n-Dibutyl Ether

Abstract

Herein, we report the catalyst-free addition of organozinc species to glycal derivatives and dihydropyrans in a toluene/n-dibutyl ether solvent mixture via a Ferrier rearrangement at room temperature. This methodology requires only a slight excess of the nucleophile and leads preferentially to the C-glycoside α-anomer. Various 1,2-dihydropyrans were assessed with a range of nucleophiles (aryl, alkynyl, alkyl) yielding the desired C-glycosides in good yield and diastereoselectivity up to 20:1.

Recent Advances on the Synthesis of C-Glycosides from 1,2-Glycals

“…On the contrary, in the case of ortho-substituted aryls the yields were diminished but the diastereoselective ratios were improved (Scheme 5). 56 The group of Savic reported an interesting Pd(II)-catalyzed reaction giving access to densely substituted transconjugated ketones 17, which show remarkable anticancer activity against HeLa, K562, and MDA-MB-453 cell lines, in some instances even out-performing cisplatin used as a standard. The reaction was carried out at 40 °C and was stereospecific in nature with trans-selectivity.…”

“…On the contrary, in the case of ortho -substituted aryls the yields were diminished but the diastereoselective ratios were improved (Scheme 5 ). 56…”