Conversion of d-Glucose to Cyclitol with Hydroxymethyl Substituent via Intramolecular Silyl Nitronate Cycloaddition Reaction: Application to Total Synthesis of (+)-Cyclophellitol
摘要:
[GRAPHICS]A diastereoisomeric mixture of 1-nitro-6-heptene-2,3,4,5-tetraol derivative (A) was prepared by Henry reaction between D-glucose-based aldehyde and nitromethane. Only the (2S)-isomer of A led to cyclitol (B) via nitronate-olefin cycloaddition on treatment with TMS-Cl and Et3N in the presence of catalytic DMAP followed by acid treatment. (+)-Cyclophellitol (1) was synthesized from B in eight steps.
Domino Reaction of Iodoglycosides: Synthesis of Carbohydrate-Based Nitroalkenes
作者:Raquel G. Soengas、Artur M. S. Silva
DOI:10.1002/ejoc.201300362
日期:2013.8
Herein we describe a tandem fragmentation/Henry reaction of iodoglycosides, which involves formation of a carbon–carbon double bond and a carbon–carbon single bond. If the fragmentation of methyl 5-iodo-D-ribofuranoside is mediated by zinc/catalytic indium in the presence of bromonitromethane, a separable mixture of a 1-nitro-5-hexene and a 1-bromo-1-nitro-5-hexene is obtained in moderate yields with