106975-25-1

Upstream product

• 64-17-5 ethanol 
• 53585-93-6 (R)-(-)-hexahydromandelic acid 
• 91057-86-2 ethyl α-hydroxy-2-oxocyclohexaneacetate 
• 75-03-6 ethyl iodide 
• 157982-30-4 (1R)-S-ethyl [1-cyclohexyl-1-tetrahydropyran-(2RS)-2-yloxy]thioacetate 
• 13275-31-5 ethyl cyclohexyloxoacetate 
• 91057-86-2 ethyl 2-hydroxy-2-(2-oxocyclohexyl)acetate 

Downstream Products

• 133420-81-2 (R)-Cyclohexyl-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-acetic acid ethyl ester 
• 133420-93-6 [(R)-2-Cyclohexyl-2-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-eth-(Z)-ylidene]-((R)-2-methoxymethyl-pyrrolidin-1-yl)-amine 
• 133420-86-7 (R)-Cyclohexyl-[dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-acetaldehyde 
• 53585-93-6 (R)-(-)-hexahydromandelic acid 

Relevant academic research and scientific papers

Catalyst-Controlled Multicomponent Aziridination of Chiral Aldehydes

A highly diastereoselective and enantioselective method for the multicomponent aziridination of chiral aldehydes has been developed with BOROX catalysts of the VANOL (3,3′-diphenyl-2,2′-bi-1-naphthol) and VAPOL (2,2′-diphenyl-(4-biphenanthrol)) ligands. Very high to perfect catalyst control is observed with most all substrates examined including aldehydes with chiral centers in the α- and β-positions. High catalyst control was also observed for a number of chiral heterocyclic aldehydes allowing for the preparation of epoxy aziridines, bis(aziridines) and ethylene diaziridines. Application of this reaction in the synthesis of β3-homo-d-alloisoleucine and β3-homo-l-isoleucine is reported.

Bronsted acid catalyzed asymmetric aldol reaction: A complementary approach to enamine catalysis

A syn-enantioselective aldol reaction has been developed using Bronsted acid catalysis based on H8-BINOL-derived phosphoric acids. This method affords an efficient synthesis of various β-hydroxy ketones, some of which could not be synthesized u

Enzymatic enantioselective reduction of α-ketoesters by a thermostable 7α-hydroxysteroid dehydrogenase from Bacteroides fragilis

A thermostable 7α-hydroxysteroid dehydrogenase (7-HSDH) from Bacteroides fragilis ATCC 25285 was cloned and over-expressed in E. coli, and its substrate specificity and stereoselectivity toward reduction of various ketones were examined. This alcohol dehydrogenase was active toward a series of aromatic and bulky aliphatic α-ketoesters. The substituents at the phenyl ring of aromatic α-ketoesters greatly affected the activity, but their effects on enantioselectivity were minimal. The synthetic application of this enzyme was then demonstrated through the preparation of a few α-hydroxy carboxylic acid esters of pharmaceutical interest.

An improved method for preparation of carboxylic esters using CsF- celite/alkyl halide/CH3CN combination

A new method for efficient and chemoselective esterification of carboxylic acids in CsF-Celite/alkyl halide/CH3CN reaction system is described.

trans-1,3-dithiane-1,3-dioxide; a chiral acyl anion equivalent. Enantioselective synthesis of α-hydroxy- carboxylic acids, esters, amides and ketones

The reaction of (R,R)-(+)-1,3-dithiane-1,3-dioxide with aldehydes has been carried out and the dithiane dioxide moiety elaborated further. (R,R)-(+)-1,3-Dithiane-1,3-dioxide gave highly diastereoselective addition products with benzaldehyde and 3,4- dimethoxybenzaldehyde and single diastereomers were isolated in 84 and 76% purified yields respectively. Under similar conditions cyclohexane carboxaldehyde gave an easily separable mixture of diastereomers in 86% total isolated yield. The adducts were transformed into protected S- ethyl α-hydroxythioesters in 95-100% ee via a Pummerer reaction and subsequent trans-thioesterification protocol using LiSEt. Using LiSEt little racemisation occurred even with aryl substituted thioesters. Further transformations of thioesters to various α-hydroxy carboxylic acid derivatives (acids, esters, amides) without racemisation have been achieved. The approach resulted in the synthesis of the dimethyl ether of (R)-(-)-3,4-dihydroxymandelic acid in its naturally occurring form. Addition of dibutyl cuprate (derived from BuMgBr and Cu(I)Br) to the thioester gave the corresponding ketone in high yield and again without racemisation.

Synthesis of O-Protected (R)-2-Hydroxy Aldehyde and Their Hydrocyanation

The synthesis of O-silyl- and O-benzyl-protected (R)-2-hydroxy aldehydes (R)-6 from (R)-2-hydroxy carboxylic acids (R)-1 is described.While attempts for their diastereoselective hydrocyanation with hydrocyanic acid and (R)-oxynitrilase as catalyst have not been successful, the cyano silylation with trimethylsilyl cyanide occurred diastereoselectively with a ratio of 81:19 preferring the threo form without racemization at C-2 of the 2-hydroxy aldehyde. Key Words : (R)-2-Hydroxy aldehydes, O-protected / Hydrocyanation

A FACILE SYNTHESIS OF (R)-(-)-HEXAHYDROMANDELIC ACID WITH FERMENTING BAKER'S YEAST

Optically pure (R)-(-)-hexahydromandelic acid has been prepared stereoselectively in two steps by the asymmetric reduction of ethyl α,2-dioxocyclohexaneacetate with fermenting baker's yeast followed by Clemmensen reduction.