Identifying stereoisomers of the asymmetric hydrogenation catalyst [Me-BPE-Rh(COD)]+BF4 -.

The performance of a catalyst used in asymmetric synthesis is likely to be dependent upon its stereoisomeric purity. An impurity was detectable by (31)P NMR in early development batches of the asymmetric hydrogenation catalyst [(S,S)-Me-BPE-Rh(COD)](+)BF(4) (-) made from the ligand bis((2S,5S)-2,5-dimethylphospholano)ethane [(S,S)-Me-BPE]. Its identity as a stereoisomer with one chiral and one meso-phospholane ring was deduced by comparison of the (31)P NMR spectra and GC traces of the ligand with a deliberately synthesized mixture of isomers.

A convergent synthesis of the 11-oxa prostaglandin analogue AL-12182.

[reaction: see text] The 11-oxa prostaglandin analogue AL-12182 1 has potent topical ocular hypotensive activity. A convergent and concise general synthesis of this class of prostanoid was developed employing a stereoselective coupling reaction between a tetrahydrofuran core electrophile and a nucleophilic omega side chain component, providing a route that should be suitable for commercial scale production. The tetrahydrofuran core was assembled from dimethyl d-malate using a stereoselective beta-hydroxy ester dianion alkylation reaction.

Asymmetric hydrogenation of a 4,4-diaryl-3-butenoate; a novel approach to sertraline.

The asymmetric hydrogenation of a selectively crystallised (E)-4,4-diaryl-3-butenoate with a rhodium-PhanePhos catalyst is described, providing an intermediate to the antidepressant sertraline.