The mechanism of the addition of lithium enolates derived from esters, ketones and aldehydes to nitrones (Mannich-type reaction) has been studied using DFT methods. While the reactions with α-methoxy and α-methyl enolates takes place through a stepwise mechanism, consisting of an initial nucleophilic attack of the enolate to the nitrone carbon followed by a second nucleophilic attack of the nit...

While Lewis acids andmetal amides are among themost frequently usedmetal species, they are believed to be incompatible when combined. Here we describe a Lewis acid/metal amide hybrid, which contains electron-withdrawing groups and basic and bulky nitrogen functional groups in the same metal complex, as a novel catalyst. We have synthesized In(N(SiMe3)2)2Cl (In(HMDS)2Cl) and In(HMDS)2OTf as Lewi...

(-)-Shikimic acid, 3, was converted into both enantiomers of epoxycyclohexenol carboxylic acid, 7, which were attached to a solid support via a photocleavable linker. Tandem acylation-1,3-dipolar cycloaddition with nitrones 11a-g yielded tetracyclic templates 12a-g. After development of several efficient coupling reactions of iodobenzyl tetracycles 12b-d and completion of extensive validation p...

The combination of lithiated alkoxyallenes with carbohydrate-derived nitrones constitutes a flexible entry to highly functionalized enantiopure 1,2-oxazine derivatives. They can be used as precursors for acyclic and cyclic carbohydrate-like products such as amino sugar alcohols, azetidine and pyrrolidine derivatives. The Lewis acid-promoted rearrangement of 1,3-dioxolanyl-substituted 1,2-oxazin...