89616-49-9

Upstream product

• 67-56-1 methanol 
• 21504-01-8 (R)-2-hydroxy-2-phenylbutanal 
• 69489-15-2 (S)-(-)-hydroxy-2-phenylbutanal 
• 15206-55-0 methyl 2-oxo-2-phenylacetate 
• 557-20-0 diethylzinc 
• 266694-57-9 Phenyl-((2R,4aR,7R,8aR)-4,4,7-trimethyl-hexahydro-1-oxa-3-thia-naphthalen-2-yl)-methanone 
• 100-52-7 benzaldehyde 
• 89556-33-2 2-<(1'S)-1'-hydroxy-1'-phenylpropyl>hexahydro-4,4,7-trimethyl-4H-1,3-benzoxathiin 
• 89616-56-8 Phenyl-((2S,4aR,7R,8aS)-4,4,7-trimethyl-hexahydro-1-oxa-3-thia-naphthalen-2-yl)-methanone 
• 89616-54-6 (R)-1-Phenyl-1-((2S,4aR,7R,8aS)-4,4,7-trimethyl-hexahydro-1-oxa-3-thia-naphthalen-2-yl)-propan-1-ol 
• 873432-44-1 (S)-(-)-1,3-diphenylpent-1-yn-3-ol 
• 93-55-0 1-phenyl-propan-1-one 
• 3966-31-2 (R)-2-hydroxy-2-phenylbutyric acid 
• 20452-67-9 phenylethylketene 

Downstream Products

• 3966-31-2 (R)-2-hydroxy-2-phenylbutyric acid 
• 24256-91-5 (S)-2-hydroxy-2-phenylbutanoic acid 

Relevant academic research and scientific papers

Addition-Rearrangement of Ketenes with Lithium N- tert-Butanesulfinamides: Enantioselective Synthesis of α,α-Disubstituted α-Hydroxycarboxylic Acid Derivatives

Addition of the lithium salts of chiral N-substituted tert-butanesulfinamides to ketenes and subsequent silylation initiates stereoselective [2,3]-rearrangement, which affords enantioenriched α,α-disubstituted α-sulfenyloxy carboxamides through a reaction

Multinuclear zinc bisamidinate catalyzed asymmetric alkylation of α-ketoesters and its unique chemoselectivity

The multinuclear Zn-bisamidinate catalyzed enantioselective addition of Et2Zn to α-ketoesters has been developed. The steric tuning of two amidinate units as well as multiple coordination on the Zn atoms play a key role in achieving high enantioselectivity (up to 98% ee) and unique chemoselectivity. The present catalyst exhibited the preferential alkylation of α-ketoesters even in the presence of aldehydes.

Lithium binaphtholate-catalyzed asymmetric addition of lithium acetylides to carbonyl compounds

The asymmetric addition of lithium acetylides to carbonyl compounds in the presence of a chiral lithium binaphtholate catalyst was developed. A procedure involving the slow addition of carbonyl compounds to lithium acetylides improved the enantioselectivi

Mechanism and scope of salen bifunctional catalysts in asymmetric aldehyde and α-ketoester alkylation

Metal complexes of C2-symmetric Lewis acid/Lewis base salen ligands provide bifunctional activation resulting in rapid rates in the enantioselective addition of diethylzinc to aldehydes (up to 92% ee). Further experiments probed the reactivity of the individual Lewis acid and Lewis base components of the catalyst and established that both moieties are essential for asymmetric catalysis. These catalysts are also effective in the asymmetric addition of diethylzinc to α-ketoesters. This finding is significant because α-ketoesters alone serve as their own ligands to accelerate racemic 1,2-carbonyl addition of Et2Zn and racemic carbonyl reduction. The latter proceeds via a metalloene pathway, and often accounts for the predominant product. Singular Lewis acid catalysts do not accelerate enantioselective 1,2-addition over these two competing paths. The bifunctional amino salen catalysts, however, rapidly provide enantioenriched 1,2-addition products in excellent yield, complete chemoselectivity, and good enantioselectivity (up to 88% ee). A library of the bifunctional amino salens was synthesized and evaluated in this reaction. The utility of the α-ketoester method has been demonstrated in the synthesis of an opiate antagonist.

Al-catalyzed enantioselective alkylation of α-ketoesters by dialkylzinc reagents. Enhancement of enantioselectivity and reactivity by an achiral Lewis base additive

An Al-catalyzed enantioselective method for additions of Me2Zn and Et2Zn to α-ketoesters bearing aromatic, alkenyl, and alkyl substituents is disclosed. Transformations are promoted in the presence of a readily available amino acid-b

Development of bifunctional salen catalysts: Rapid, chemoselective alkylations of α-ketoesters

Lewis acid-Lewis base salen complexes have been identified as highly efficient catalysts for the addition of dialkylzincs to α-ketoesters. In contrast to aldehydes or ketones, the reaction between diethylzinc and α-ketoesters is significant in the absence of catalyst. In the presence of catalyst, the reaction rate is increased over 100-fold relative to the background. Furthermore, the reduction product, which is a major coproduct with other catalysts, is not observed with these bifunctional salens. As a result, high yields of the addition products can be obtained (57-99%). Both the Lewis acid and Lewis base portions of the catalyst are critical to the reactivity and selectivity. The two separate portions of the catalyst have been shown to function in a cooperative manner. Copyright

The First Catalytic Asymmetric Addition of Dialkylzincs to α-Ketoesters

(Matrix Presented) The first catalytic, enantioselective addition of organozinc reagents to α-ketoesters is described. Modular bifunctional salen catalysts that contain Lewis acid and Lewis base activating groups accelerate the carbonyl addition to a much greater extent than the competing carbonyl reduction. α-Hydroxyesters containing new quaternary stereogenic centers are obtained in high yield and moderate enantiomeric excess. Enrichment to 98% ee can be effected by recrystallization of the corresponding α-hydroxy acid.

Asymmetric Syntheses Based on 1,3-Oxathianes. 2. Synthesis of Chiral Tertiary α-Hydroxy Aldehydes, α-Hydroxy Acids, Glycols (RR'C(OH)CH2OH), and Carbinols (RR'C(OH)CH3) in High Enantiomeric Purity

A chiral 1,3-oxathiane (5) prepared from (+)-pulegone in three steps is converted to diastereomerically pure equatorial 2-acyl derivatives by lithiation, condensation with aldehydes, and Me2SO oxidation.Reaction of the resulting ketones with Grignard reagents at -78 deg C again proceeds highly stereoselectively (diastereomer excess generally above 90percent) according to Cram's rule (cyclic model).The resulting tertiary carbinols when cleaved with NCS/AgNO3 give chiral tertiary α-hydroxy aldehydes, RR'C(OH)CHO, plus a mixture of epimeric sultines which may be readily reconverted to the starting oxathiane.The hydroxy aldehydes have been oxidized to chiral tertiary α-hydroxy acids, RR'C(OH)CO2H, and reduced to primary-tertiary glycols, RR'C(OH)CH2OH, and further to tertiary carbinols, RR'C(OH)CH3, all with over 90percent ee.The opposite enantiomers of these compounds (again >90percent ee) may be obtained by starting with a diastereomeric 1,3-oxathiane (6), also available from (+)-pulegone.The configurations of the chiral products may be deduced from the manner of preparation and the assumption that Cram's rule is valid and agree with prior assignments in the literature.