96948-92-4

Upstream product

• 165881-60-7 (R)-2-benzyl-2-methyloxirane 
• 96949-05-2 (R)-2-Hydroxy-2-methyl-3-phenyl-propionaldehyde 
• 56269-86-4 (R,S)-2-hydroxy-2-methyl-3-phenylpropanoic acid 
• 100-39-0 benzyl bromide 
• 107968-18-3 2-((4S,5S)-4,5-Bis-methoxymethyl-2-phenyl-[1,3]dioxolan-2-yl)-4-trimethylsilanyl-but-3-yn-2-ol 
• 107954-37-0 (S)-2-((4S,5S)-4,5-Bis-methoxymethyl-2-phenyl-[1,3]dioxolan-2-yl)-but-3-yn-2-ol 
• 108007-12-1 (S)-2-((4S,5S)-4,5-Bis-methoxymethyl-2-phenyl-[1,3]dioxolan-2-yl)-but-3-en-2-ol 
• 107968-12-7 1-((4S,5S)-4,5-Bis-methoxymethyl-2-phenyl-[1,3]dioxolan-2-yl)-ethanol 
• 107968-14-9 2-keto-1-phenyl-1-propanone (2S,3S)-1,4-dimethoxy-2,3-butylene acetal 
• 73611-99-1 2-Hydroxypropiophenone dimethylacetal 
• 36099-42-0 (+/-)-2-methyl-3-phenyl-1,2-epoxypropane 
• 6921-34-2 benzylmagnesium chloride 
• 444308-45-6 (1S,2R,5R,7S)-5-[(R)-2'-hydroxy-1'-phenyl-2'-propyl]-10,10-dimethyl-4-oxa-6-thiatricyclo[7.1.1.0^2,7]undecane 
• 96948-91-3 (R)-1-Phenyl-2-((2R,7R)-4,4,7-trimethyl-hexahydro-1-oxa-3-thia-naphthalen-2-yl)-propan-2-ol 

Downstream Products

• 96948-95-7 Acetic acid (R)-1-benzyl-2-cyano-1-methyl-ethyl ester 
• 96949-01-8 Acetic acid (R)-3-acetoxy-1-benzyl-1-methyl-propyl ester 
• 96948-98-0 (R)-(+)-3-hydroxy-3-methyl-4-phenylbutanoic acid 
• 96948-94-6 (R)-(-)-3-hydroxy-3-methyl-4-phenylbutanonitrile 
• 96948-99-1 (R)-(+)-3-methyl-4-phenyl-1,3-butanediol 
• 96948-93-5 (S)-1-Phenyl-2-(toluene-4-sulfonylmethoxy)-propan-2-ol 
• 96948-93-5 Toluene-4-sulfonic acid (R)-2-hydroxy-2-methyl-3-phenyl-propyl ester 

Relevant academic research and scientific papers

Synthesis of Chiral Tertiary Boronic Esters by Oxime-Directed Catalytic Asymmetric Hydroboration

Chiral boronic esters are useful intermediates in asymmetric synthesis. We have previously shown that carbonyl-directed catalytic asymmetric hydroboration (CAHB) is an efficient approach to the synthesis of functionalized primary and secondary chiral boronic esters. We now report that the oxime-directed CAHB of alkyl-substituted methylidene and trisubstituted alkene substrates by pinacolborane (pinBH) affords oxime-containing chiral tertiary boronic esters with yields up to 87 % and enantiomeric ratios up to 96:4 e.r. The utility of the method is demonstrated by the formation of chiral diols and O-substituted hydroxylamines, the generation of quaternary carbon stereocenters through carbon-carbon coupling reactions, and the preparation of chiral 3,4,4-trisubstituted isoxazolines.

Preparation of substituted enol derivatives from terminal alkynes and their synthetic utility

Stereodefined enol derivatives of aldehydes are prepared from terminal alkynes. Specifically, terminal alkynes are known to undergo Cp2ZrCl2-catalyzed methylalumination. Here, we show that the resultant vinylalanes can be oxygenated with peroxyzinc species to generate trisubstituted enolates. Electrophilic trapping with carboxylic anydrides or silyl triflates yields trisubstituted enol esters or silanes, respectively. The tandem carbometalation/oxygenation tolerates free and protected alcohols, heterocycles, olefins, and nitriles. Stereodefined enol esters can undergo asymmetric dihydroxylation to yield optically active α-hydroxy aldehydes. Reduction with NaBH4 provides the diols of 1,1-disubstituted olefins in excellent ee. An application of this methodology to the enantioselective synthesis of the insect pheromone frontalin is presented. Finally, α-hydroxy aldehydes are shown to undergo homologation to a terminal alkyne, reductive amination, oxidation and olefination. Preliminary results indicate that tandem carbometalation/amination can be accomplished with azodicarboxylates. In this way, ene-hydrazines are formed in excellent yield. Copyright

Diastereoselective addition of grignard reagents to chiral α-ketoimides derived from Oppolzer's sultam

Additions of various Grignard reagents to N-pyruvoyl- (3) and N-phenylglyoxyloyl-(2R)-bornane-10,2-sultam (4) under thermal and Lewis-acid catalytic conditions are studied. High diastereoselectivity was observed in these reactions, and in the case of vinylmagnesium bromide additions to α-ketoimide 4 a change of direction of asymmetric induction was found.

Highly diastereoselective nucleophilic additions using a novel myrtenal-derived oxathiane as a chiral auxiliary

The synthesis of novel oxathiane 3 and its acetyl derivative 12, from commercially available (-)-myrtenal 4, is described. The addition of several nucleophilic reagents to 12 furnished the corresponding tertiary carbinols in highly diastereomeric excess. The hydrolysis of 11a, b yielded the expected α-hydroxycarbonyl compounds in excellent enantiomeric excess.

An efficient] large-scale synthesis of (R)-(-)-mevalonolactone using simple biological and chemical catalysts

Natural (R)-(-)-mevalonolactone (2) was synthesized in eight steps in 55% total yield and >99% ee employing an enantioconvergent chemoenzymatic route. In the key step, 2-benzyl-2-methyloxirane (±)-3 was deracemized on a large scale (10 g) using lyophilized cells of Nocardia EH1 and sulfuric acid. The product diol (S)-4 was isolated in 94% chemical yield and 94% optical purity.

Chemoenzymatic deracemization of (±)-2,2-disubstituted oxiranes

The preparation of vicinal diols in up to 98% e.e. and 98% yield from the corresponding (±)-2,2-disubstituted epoxides was achieved via an enantioconvergent two-step hydrolysis: Thus, enantioselective enzymatic hydrolysis of the (S)-epoxide proceeded with retention of configuration furnishing the corresponding (S)-diol. In a subsequent step, the remaining (R)-oxirane was hydrolyzed during workup under acid catalysis with complete inversion of configuration yielding the (5)-diol. A detailed study of the latter reaction revealed that the experimental conditions have to be carefully chosen with respect to (i) nature of the acid, (ii) the solvent, and (iii) its water content to avoid racemization.

Deracemization of (±)-2,2-disubstituted epoxides via enantioconvergent chemoenzymatic hydrolysis using nocardia EH1 epoxide hydrolase and sulfuric acid

2-Substituted (S)-1,2-diols were prepared in a one-pot procedure with >90% ee and >90% isolated yield via deracemization of (±)-2,2-disubstituted oxiranes through sequential (i) biocatalytic asymmetric hydrolysis using Nocardia EH1 epoxide hydrolase and (

Enantioselective Synthesis of 2-Methyl-2-hydroxy-γ-butyrolactone and Its Application in the Asymmetric Synthesis of Frontalin and Mevalonolactone

The asymmetric hydroxylation of the enolates of fully substituted acyclic ester 8 and lactone 10 with (camphorylsulfonyl)oxaziridines 1a - c was studied.The stereoselectivities of the tertiary α-hydroxy carbonyl products were highly dependent on the enolate structure, the oxidizing reagents, and the reaction conditions.While high diastereoselectivity (up to 94percent) was obtained for enolates of fully substituted menthol ester 8 with substoichiometric amounts of oxaziridine 1a, the yields were unsatisfactory.On the other hand, the enantioselective α-hydroxylation of the sodium enolate of 2-methyl-γ-butyrolactone (10) with oxaziridine (1c) afforded α-hydroxy lactone 11a in 70percent yield and 84percent ee.The enantiomeric excess was improved to >93percent ee by crystallization of the corresponding benzoyl ester 11c.The utility of both enantiomers of 11c were demonstrated in the formal asymmetric syntheses of the pheromone, (1S,5R)-(-)-frontalin (13) and in the asymmetric synthesis of (R)-(-)-mevalonolactone (20).

Asymmetric Synthesis Using Chiral Acetals: Studies on the Nucleophilic Addition of Organometallics to Chiral α-Keto Acetals in Open-Chain Systems

Nucleophilic addition of organometallic reagents (Grignard reagents and organolithium reagents) to three chiral α-keto acetals (1a-c) in open-chain systems was studied.The reactions of the chiral α-keto acetals (1a,1b) having a chiral auxiliary as a keton

DIASTEREOSELECTIVE NUCLEOPHILIC ADDITION TO CHIRAL OPEN-CHAIN α-KETOACETALS: SYNTHESIS OF (R)- AND (S)-MEVALOLACTONE

Highly stereoselective addition of Grignard reagents to chiral open-chain α-ketoacetals (3a,3b) has been attained.Application of the reaction to syntheses of the key intermediates (6,8) for (R)- and (S)-mevalolactone is also described.