6191-36-2

Upstream product

• 13448-80-1 methyl R-(-)-atrolactate 
• 136347-13-2 (S)-2-hydroxy-3-<(4-methylphenyl)sulfenyl>-2-propanamide 
• 169221-14-1 (R)-(+)-2-hydroxy-2-phenylpropanenitrile 
• 532-28-5 (RS)-mandelonitrile 
• 198906-22-8 (1'R/S,2S,4S,5S)-2-[(1'-Cyano-1'-phenyl)methoxy]-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidin-2-one 
• 169139-18-8 (1'R,2S,4S,5S)-2-[(1'-Cyano-1'-phenyl)ethoxy]-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidin-2-one 
• 52154-24-2 (R)-p-tolylsulfinylacetophenone 
• 136347-09-6 (S₂,R_S)-2-hydroxy-3-<(4-methylphenyl)sulfinyl>-2-phenylpropanenitrile 

Downstream Products

• 3966-30-1 (R)-Atrolactic acid 

Relevant academic research and scientific papers

Stereoselective umpolung reactions with metalated p-chiral cyanohydrin phosphates-enantioselective synthesis of tertiary cyanohydrins

We present the first cyanohydrin derivative 4 that allows diastereoselective umpolung reactions. In 4 the OH group of the cyanohydrin is linked with a chiral phosphate, which can be removed hydrolytically after asymmetric synthesis. Cyclization of pseudoephedrine 1d with POCl3 gave 2d. This was followed by addition of racemic benzaldehyde cyanohydrin 3 to give the key intermediate 4d. With complete retention of the configuration at phosphorus. Deprotonation of 4d, followed by addition of a wide variety of electrophiles afforded the crystalline products 5 with high diastereomeric excesses (de up to 94%). High asymmetric induction was also achieved for the reaction of 4-Li+ with acyl halides, α-bromoacetates, 2-cycloalkenones, α,β-unsaturated esters, and γ-bromoacetates. Lewis acid assisted hydrolysis proceeded without racemization and gave high yields of ketone cyanohydrins 6. From the ring-opened chiral auxiliary 7, optically pure pseudoephedrine 1 was readily recovered by acid hydrolysis. Optically pure (R) and (S) ketone cyanohydrins are now accessible in a very general strategy, which circumvents the substrate limitations of enzymatic synthesis.

Ein chirales Cyanhydrinphosphat als umgepolte Carbonylverbindung - stereoselektive Synthese von tertiaeren Cyanhydrinen

Stichworte: Asymmetrische Synthesen * Cyanhydrine * Umpolung * Wirkstoffsynthesen

Reactions of chiral β-ketosulfoxides with Et2AlCN: Asymmetric synthesis of cyanohydrin derivatives

The reaction of chiral p-tolylsulfinylmethyl ketones (R-CO-CH2-SOTol, R=Ph, Et and t-Bu) with Et2AlCN, yields almost optically pure sulfinyl cyanohydrins (d.e. ≥ 96%). The reaction was quicker in the presence of ZnCl2, but