An electrophile-mediated cyclization on the 1,6-anhydro-d-glucopyranose framework
摘要:
Iodocyclization of O-tributylstannyl-D-glucal with iodine in acetonitrile gave 1,6-anhydro-2-deoxy-2-iodo-beta-D-glucopyranose (1) in high yield. The 3,4-di-O-acetyl derivative of 1 could be converted into the corresponding 2-deoxy compound and into the 2-C-allyl-2-deoxy branched sugar (5) by treatment with tributylstannane and allyltributylstannane, respectively. Controlled alkaline hydrolysis of 5 gave the 4-monoacetyl derivative. Complete hydrolysis of 5 gave the 3,4-diol, which underwent a 5-exo cyclization by treatment with N-bromosuccinimide. H-1 NMR spectroscopy and X-ray analysis showed that the cyclized product has the B3,O conformation in its pyranose ring, which is trans-fused to the newly formed tetrahydrofuran ring.
Water Compatible Hypophosphites-<i>d</i><sub>2</sub> Reagents: Deuteration Reaction via Deutero-deiodination in Aqueous Solution
作者:Zejin Song、Jing Zeng、Ting Li、Xiang Zhao、Jing Fang、Lingkui Meng、Qian Wan
DOI:10.1021/acs.orglett.0c00001
日期:2020.3.6
conventional deuteration approaches which typically entail deuterated solvents and/or moisture exclusion, an unprecedented deutero-deiodination reaction attainable in aqueous (H2O) solution is presented herein. By utilizing the stability of inorganic deuterated calcium/sodium hypophosphites against wayward H/D isotopicexchange within pH 2.5-11.7, these shelf-stable, nontoxic, cost-effective, and environmentally
New reductive deiodination reaction by hydrogen atom transfer from cyclohexane
作者:Jean Boivin、Béatrice Quiclet-Sire、Laure Ramos、Samir Z. Zard
DOI:10.1039/a607459f
日期:——
Secondary iodides flanked by one or more inductive electron-withdrawing
groups can be reduced via a radical chain reaction involving a
hydrogen atom transfer from cyclohexane, the process being triggered by a
small amount of an initiator such as dilauroyl peroxide.