Stereoselective Synthesis of Glycomimetics by Photocatalytic One-Pot C(sp³)─H Acylation and Ring Contraction

Glycomimetics, structural mimics of natural carbohydrates such as C-glycosides and carbasugars, are important therapeutic leads for treating a variety of diseases. However, the structural and stereochemical complexity of glycomimetics poses daunting challenges to synthetic chemists and is incompatible with diversity-oriented synthetic approaches. Herein, we develop a facile and general method for the stereoselective synthesis of C-acyl glycosides and carbasugars from readily accessible and stable 1-deoxyglycosides via photo-HAT/nickel dual catalysis. The reaction proceeds in one-pot under mild conditions and exhibits high stereoselectivity across a wide range of glycosyl units, illustrating the potential of this method in the preparation of structurally diverse and densely functionalized carbasugars. The synthetic utility of this strategy is further demonstrated in the synthesis of challenging cyclopentanepentol, an analogue of calditol.