Carboxylic and Thiocarboxylic Esters

1 Synthesis. - A report on perspectives on alkyl carbonates in organic synthesis has appeared. This contains applications of alkyl carbonate protecting groups in carbohydrate chemistry, carbonate exchange reactions and subsequent modifications as applied to carbohydrate derivatives and promotion of glycosylations.  

Carbohydrate Chemistry, Volume 34 The Royal Society of Chemistry, 2003 

Reagents i, Pr 2NEt, Benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate 

Preparation of the Fmoc protected 6 was accomplished and used in oligosaccharide synthesis. After formation of the trichloroacetimidate donor and glycosylation, the Fmoc group was quantitatively cleaved using mild basic conditions.The synthesis of conandroside 7 was accomplished using conventional methods, with the key intermediate being 2-(3,4-di-0-benzyloxyphenyl)ethyl 2,6-di-0-acetyl-4-0-( ,Z)-3,4-0-benzylcafleoyl)-p-D- 

Reagents i, Et3B-BuC02BEt2, hexane ii, Bu2Sn(acac)2 iii, MntCOCI, NMI 

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