Asymmetric cyclopropanation of allylic ethers: cleavage and regeneration of the chiral auxiliary
                                
                                    
                                        作者:Andre B. Charette、Bernard Cote                                    
                                    
                                        DOI:10.1021/jo00056a028
                                    
                                    
                                        日期:1993.2
                                    
                                    The ring contraction reaction of 2-O-(trifluoromethyl)sulfonyl]oxy]-beta-D-glucopyranosides and their corresponding a-anomers is reported. The rearrangement was shown to occur under extremely mild basic conditions to allow isolation of acid-sensitive optically active substituted cyclopropylmethanols. The chiral auxiliary can be regenerated by converting the C-glucofuranoside, byproduct of the rearrangement, into tri-O-benzyl-D-glucal (two steps).