3、ldprimaryalcoholofapyranoside.2、70%HCOOH,cat.HClO4,50-550,goodyields.3、HCOOH,BF3*2MeOH,90%yield.Cleavage1、KHCO3,H2O,MeOH,20°C,3days2、Dil.NH3,pH11.2,220°C,62%yield.I.W.Hughes,F.Smith,andM.Webb,J.Chem.Soc.,3437(1949).FormationAcetateEster(ROAc):1、Ac2O,Pyr,20°,12h,100%yield。2、CH3COCl,25’,
4、16h,67-79%yield.3、Ac2OorAcCl,Pyr,DMAP,24-80°,l-40h,72-95%yield。NaH,93%yield.Primaryalcohols4、5、Me(OMe)3,TsOH,1.5h,thenH2Ofor30min6、Ac2O,Sc(NTf2)3,CH3CN,00C,1h,99%yield.Themethodisalsogoodfortertiaryalcohols.1.K2CO3,MeOH,H2O,200C,1h,100%yield。WhencatalyticNaOMeisusedasthebaseinmethanol,
5、theMethodisreferredtoastheZemplende-O-acetylation.2、KCN,95%EtOH,200Ctoreflux,12h,93%yield.3、Guanidine,EtOH,CH2Cl2,rt,85-100%yield.4、BF3*Et2O,wetCH3CN,96%yieldCleavage1、(ClCH2CO)2O,Pyr,00C”,70-90%yield.2、ClCH,COCl,Pyr,ether,87%yield.3、PPh3,DEAD,ClCH2CO2H,73%yield.4、Vinylchloroacetate,Cp
6、*2Sm(THF)2,toluene,rt,99%yield.WithSmI2ascatalyst,theyieldis79%.ChloroacetateEster:ClCH2CO2RFormationCleavage1、HSCH2CH2NH2orH2NCH2CH2NH2oro-phenylenediamine,Pyr,Et3N,1h,rt.2、Thiourea,NaHCO3,EtOH,700C,5h,70%yield.3、H2O,Pyr,pH6.7,20h,100%yield.4、NH2NHC(S)SH,lutidine,AcOH,2-20min,rt,88-99
7、%yield.1.Cl3CCOCl,Pyr,DMF,200C,2days,60-90%yield.TrichloroacetateEster:RO2CCCl3Formation1.NH3,EtOH,CHCl3,200C,6h,81%yield.Cleavage2KOH,MeOH,72%yield.Aformateesterwasnothydrolyzedundertheseconditions.V.Schwarz,Collect.Czech.Chem.Commun.,27,2567(1962).S.Bailey,A.Teerawutgulrag,andE.J.T