A branched Man(5) oligosaccharide has been synthesized by sequential regioselective glycosylations on a mannose-tetraol with n-pentenyl orthoester glycosyl-donors promoted by NIS/BF(3)·Et(2)O, in CH(2)Cl(2). An extended n-pentenyl chain was incorporated into the tetraol acceptor to facilitate (a) the solubility of the starting tetraol in CH(2)Cl(2), and (b) future manipulations at the reducing ...

Camphor-derived oxazoline-N-oxides are versatile dipoles in a new kind of asymmetric [2+3] cycloadditions. Recent applications of this methodology allowed the stereoselective syntheses of several β-lactones natural products such as 1233A and tetrahydrolipstatine. Two formal syntheses of β-lactams antibiotics, β-methyl thienamycin and carpetimycin A, have also been achieved using this type of cy...

A sugar poly(orthoester)-based drug delivery system was constructed to achieve acidity-enhanced drug delivery and cell killing.

The preparation o f the daphnane proto type polyfunctional diterpene resiniferonol from resiniferatoxin (1) contained in latex from Euphorbia unispina or E. poisonii was modified to con­ vert in an 'early ' fraction o f the acetone extract the extremely irritant 1 to the much less irritant 9,13,14-ortho(phenylacetate) 2 by transesterification. 2 was obtained in good yields and can be handled co...

Glycosyl halides are a very valuable and versatile group of synthetic intermediates widely used in carbohydrate chemistry for the ready functionalization at the anomeric carbon. Thus, glycosyl halides can be easily converted into O-glycosides, C-glycosides, or glycals via the generation of intermediate anomeric carbocations, radicals, or cabanions. Because of their moderate stability, glycosyl ...

Copper-catalyzed reactions include the enantioselective conjugate addition and the SN2′ substitution. We describe the genesis of these reactions, the choice of the primary organometallic reagent, and our studies on finding new Michael acceptors and new ligands. We also report on the use of the zinc enolate generated upon conjugate addition. INTRODUCTION Organocopper chemistry has found widespre...