Stereocontrolled Synthesis of 2-Deoxy-galactopyranosides via Isopropylidene-Protected 6-O-Silylated Donors

• DOI: 10.1021/acs.orglett.8b00632
• Publication Date: 2018-03-27T12:41:54Z
• Authors: Dan-Mei Yang; Yue Chen; Ryan P. Sweeney; Todd L. Lowary; Xing-Yong Liang
• Keywords: 01 natural sciences; 3. Good health; 0104 chemical sciences

The stereocontrolled synthesis of 2-deoxy-d-arabino-hexopyranosides ("galactopyranosides") using 3,4-O-isopropylidene-6-O-tert-butyldiphenylsilyl-protected glycosyl donors is reported. 2-Deoxy-thioglycoside 3e gives excellent α-selectivity, while galactal 9 leads to, in a two-step protocol, 2-deoxy-β-glycosides high stereoselectivity. selectivity both reagents believed to arise from the combination isopropylidene acetal spanning O-3 and O-4 together with sterically demanding silyl group on O-6. utility method was demonstrated through trisaccharide that contains 2-deoxy α- β-d-galactopyranosyl residues.