Controlling diastereoselectivity in the reactions of enantiomerically pure alpha-bromoacyl-imidazolidinones with nitrogen nucleophiles: substitution reactions with retention or inversion of configuration

Diastereoselective substitution reactions of [small alpha]-bromoacyl-imidazolidinones with nitrogen nucleophiles can be promoted with either retention or inversion of configuration by carrying out reactions under epimerising or non-epimerising conditions.     

Electrophilic amination of enolates with oxaziridines: effects of oxaziridine structure and reaction conditions

A range of N-alkoxycarbonyl- and N-carboxamido-oxaziridines has been prepared to test the effects of oxaziridine structure on yields of enolate amination product. Side-products arising from reaction of aldehyde-derived oxaziridines with base were identified, while a ketone-derived oxaziridine afforded moderate yields of amination product with stabilised carbanions.     

Oxaziridine-mediated amination of branched allylic sulfides: stereospecific formation of allylic amine derivatives via [2,3]-sigmatropic rearrangement

Reaction of branched allylic sulfides with the N-Boc-oxaziridine 1 results in [2,3]-sigmatropic rearrangement of the intermediate allylic N-Boc-sulfimides with a high level of chirality transfer. The first example of formation of a quaternary stereocenter using this transformation is reported.     

Steady vortical flow around a finite plate

An explicit solution for a layer of fluid with constant vorticitysurrounding a thin plate of finite length is obtained usingelementary conformal mapping methods. In the limit of largeplate length the behaviour of the solution near the ends ofthe plate tends to that of the previously known solution fora semi-infinite plate. Contour dynamics is used to investigatethe stability of the steady solutions.