The stereoselective synthesis of diethyl (S)or (R)-IX-[( O-pivaloylhexapyranosyl)amino]benzylphosphonates is achieved via Lewis acid catalyzed addition of diethyl phosphite to O-pivaloylated Nbenzylidene-{3-D-galactosylamine or N-benzylidene-IX-D-arabinopyranosylamine. The process can also be performed by a one-pot procedure selectively giving (S)-aminophosphonic acid derivatives from galactosy...

A novel way of combining chiral auxiliaries and substrate directable reactions is described that employs a three-step sequence of aldol/cyclopropanation/retro-aldol reactions for the asymmetric synthesis of enantiopure cyclopropane-carboxaldehydes. In the first step, reaction of the boron enolate of (S)-N-propionyl-5,5-dimethyl-oxazolidin-2-one with a series of alpha,beta-unsaturated aldehydes ...

Introduction Ibuprofen is a non-steroidal anti-inflammatory drug (NSAI) from the family of the arylpropionic acids (Lombardino, 1985). Despite ibuprofen continues to be marketed as racemate, it has been demonstrated that only the (S)enantiomer is responsible for the desired therapeutic effects (Adams et al., 1976). (R)Enantiomer shows some risk of toxicity due to be stored into adipose tissue a...

It is well recognized that molecular chirality is essential to life processes, and that most biologically active compounds controlling physiological functions of living organisms are chiral. Hence, in the structural study of biologically active compounds, including natural products, determination of absolute configuration becomes the first major issue. The second issue is chiral synthesis of na...

Introduction An economical way to obtain optically active β-lactam derivatives is the use of amino acids as chiral auxiliaries in Staudinger reaction (Bose et al., 1985). This strategy has been used for asymmetric synthesis of bicyclic β-lactam compounds, such as 2-isocephems, from threonine (Tenneson and Belleau, 1980). In addition, β-lactams obtained by this method are useful as versatile int...