Formation of β-lactams fused to the pyranoid ring via the Mitsunobu reaction
摘要:
N-Tosyl-2-C-carbamoyl glycosides having the alpha-L-arabino- and beta-D-xylo- configuration form under Mitsunobu conditions 2-C:3-N-carbonyl-2,3-dideoxy-3-N-tosylamino-alpha-L-lyxo and beta-D-arabinopyranosides, respectively, having the beta-lactam ring fused to the pyranoid one; neither the formation of the gamma-lactam ring nor that of the 3,4-epoxide were observed. The gamma-lactam 2-C:4-N-carbonyl-2,4-dideoxy-4-N-tosylamino-beta-D-xylopyranoside can be obtained after protection of the 3-hydroxy group in the starting glycoside of alpha-L-arabino-configuration. The structure and configuration of methyl 2-C:3-N-carbonyl-2,3-dideoxy-3-N-tosylamino-beta-D-ribopyranoside and methyl 2-C:3-N-carbonyl-2,3-dideoxy-3-N-tosylamino-beta-D-erythro-pyranosid-4-ulose were proved by X-ray crystallography. (C) 1998 Elsevier Science Ltd. All rights reserved.
Delineating The Multiple Roles of B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> in the Chemoselective Deoxygenation of Unsaturated Polyols
作者:Trandon A. Bender、Jennifer A. Dabrowski、Michel R. Gagné
DOI:10.1021/acscatal.6b02551
日期:2016.12.2
A set of B(C6F5)3-catalyzed methods for diversification of unsaturated carbohydrate derived substrates is disclosed. Lewis acid cyclization, allylic alcohol hydrosilylation, and selective silyl group exchange is achieved with this single versatile catalyst. Allylic polyols and highly enriched (Z)-triols are obtained in high yields under a single-step protocol.
公开了一组B(C 6 F 5)3催化的使不饱和碳水化合物衍生的底物多样化的方法。用这种单一的多功能催化剂可实现路易斯酸环化,烯丙基醇氢化硅烷化和选择性甲硅烷基交换。烯丙基多元醇和高浓缩的(Z)-三醇可在一步操作下以高收率获得。
Chmielewski, Marek; Kaluza, Zbigniew; Abramski, Wojciech, Bulletin of the Polish Academy of Sciences: Chemistry, 1987, vol. 35, # 7-8, p. 245 - 249