A stereochemically general synthesis of methyl 2,4,6-trideoxy-4-methylthio-α-D-ribo-pyranoside, the thio sugar of esperamicin A1
摘要:
A stereochemically general synthesis of methyl 2,4,6-trideoxy-4-methylthio-alpha-D-ribo-pyranoside (1b), the thio sugar isolated from esperamicin, is described. The synthesis involves the neighboring group assisted delivery of a sulfur nucleophile to C(5) of epoxyalcohol 6 via aniline promoted cyclization of thioimidazolide 7.
Eu(OTf)<sub>3</sub>-Catalyzed Highly Regioselective Nucleophilic Ring Opening of 2,3-Epoxy Alcohols: An Efficient Entry to 3-Substituted 1,2-Diol Derivatives
In our study of the totalsynthesis of (+)-irciniastatin A, we found a need to develop a method that enables a C3-selective nucleophilicringopening of 2,3-epoxyalcohol by MeOH, by which we found that the use of combined catalytic amounts of Eu(OTf)3 and 2,6-di-tert-butyl-4-methylpyridine (DTBMP) enables the intended transformation to obtain 3-methoxy-1,2-diol efficiently. Promising features of a
Studies in macrolide synthesis: A sequential aldol/glycosylation approach to the synthesis of concanamycin A
作者:Ian Paterson、Malcolm D. McLeod
DOI:10.1016/0040-4039(95)01913-3
日期:1995.12
The C19–C28 model fragment 2 of concanamycin A (1) was prepared by a Mukaiyama aldol reaction between silyl enol ether 11 and aldehyde 4 to give 7, followed by glycosylation with activated sugar 14 or 15.
A highly stereoselective synthesis of (+)-cryptocarya diacetate is achieved through our recently developed strategy for the construction of 1,3-diols via Prins cyclisation. The route relies mainly on the reductive cleavage of allylic ethers, ozonolysis and Wittig olefination along with Prins cyclisation.
A highly convergent total synthesis of macrocyclic lactam glycoside vicenistatin is described. Key features of the synthesis include rapid assembly of the macrolactam part and macrocyclic ring closure via intramolecular Stille coupling.
Asymmetric synthesis of the hydroxylamino sugar of calicheamicin
作者:William R. Roush、Bruce C. Follows
DOI:10.1016/s0040-4039(00)73286-2
日期:1994.7
for the conversion of 2,3-epoxyalcohols to N-alkoxy oxazolidinones via the DBU promoted cyclizations of 2,3-epoxy-N-alkoxyurethanes has been developed and applied to the first asymmetric synthesis of the calicheamicin hydroxylamino sugar, 7.