19068-48-5

Upstream product

• 79120-96-0 (R)-(-)-3-phenylbutan-2-one 
• 591-51-5 phenyllithium 
• 1758-32-3 (2R,3R)-2,3-epoxybutane 
• 769-59-5 3-phenyl-butan-2-one 
• 103-79-7 1-phenyl-acetone 
• 873-66-5 1-propenylbenzene 
• 74-88-4 methyl iodide 
• 917-64-6 methyl magnesium iodide 
• 34713-70-7 2-Phenylpropanal 
• 31508-44-8 2-phenylpropionic acid methyl ester 
• 492-37-5 hydratropic acid 
• 1123-85-9 (RS)-2-phenyl-1-propanol 
• 135-98-8 sec-Butylbenzene 
• 21490-63-1 2,3-trans-epoxybutane 

Downstream Products

• 78549-49-2 (2R,3R)-3-phenylbut-2-yl acetate 
• 1499-67-8 (2R,3R)-3-cyclohexyl-butan-2-ol 

Relevant academic research and scientific papers

Biocatalytic Asymmetric Hydroxylation of Hydrocarbons with the Topsoil-Microorganism Bacillus megaterium

A Bacillus megaterium strain was isolated from topsoil by a selective screening procedure with allylbenzene as a xenobiotic substrate. This strain performed the hydroxylation chemoselectively (no arene oxidation and overoxidized products) and enantioselectively (up to 99% ee) in the benzylic and nonbenzylic positions of a variety of unfunctionalized arylalkanes. Salycilate and phenobarbital, which are potent inducers of cytochrome P-450 activity, changed the regioselectivity of the microbial CH insertion, without an effect on the enantioselectivity. The biotransformation conditions were optimized in regard to product yield and enantioselectivity by variation of the oxygen-gas supply and the time of the substrate addition. The different product distributions (α- versus β-hydroxylated product) that are obtained on induction of cytochrome P-450 enzyme activity demonstrate the involvement of two or more hydroxylating enzymes with distinct regioselectivities in this biotransformation. An oxygen-rebound mechanism is assumed for the cytochrome P-450-type monooxygenase activity, in which steric interactions between the substrate and the enzyme determine the preferred face of the hydroxy-group transfer to the radical intermediate.

Enantioselective Copper-Catalyzed Methylboration of Alkenes

An enantioselective Cu-catalyzed borylative cross-coupling reaction of alkenes, bis(pinacolato)diboron (B2(pin)2), and methyl iodide is reported. Alkenes including styrenes, β-substituted styrenes, and challenging aliphatic olefins were smoothly transferred to the desired methylboration products with excellent diastereoselectivities (dr up to >99:1) and enantioselectivities (er up to 99:1). The utility of this process was demonstrated by the synthesis of naproxen and formal synthesis of two natural products.

Dynamic Reductive Kinetic Resolution of Benzyl Ketones using Alcohol Dehydrogenases and Anion Exchange Resins

Dynamic reductive kinetic resolutions of racemic 3-arylalkanones have been performed by the proper combination of an alcohol dehydrogenase and a basic anionic resin. The best results were found for the bioreduction with the alcohol dehydrogenase type A from Rhodococcus ruber DSM 44541 overexpressed in Escherichia coli (E. coli/ADH-A) and the commercially available evo-1.1.200, while the Amberlite IRA-440 C and the DOWEX-MWA-1 resins allowed efficient in situ racemizations. Reaction conditions were optimized in terms of enzyme source and loading, type and amount of resin, pH, temperature and reaction times, obtaining a series of (R,R)-substituted propan-2-ols with good conversions and both diastereoselectivity and stereoselectivity. As a proof of concept, the subsequent intramolecular cyclization of a selected propan-2-ol substrate afforded a valuable isochroman heterocycle without any loss of the optical purity.

Samarium diiodide-promoted diiodomethylation of carbonyl compounds with iodoform. Synthetic applications of diiodoalcohols

A rapid and effective diiodomethylation of carbonyl compounds using SmI2 and iodoform is described. Transformations of the obtained diiodoalcohols 2 into α-iodoaldehydes 5 and α-hydroxyacids 6 is also reported.

Enantiopreference of Lipase from Pseudomonas cepacia toward Primary Alcohols

We propose an empirical rule that predicts which enantiomer of primary alcohol reacts faster in reactions catalyzed by lipase from Pseudomonas cepacia (PCL).This rule, based on the size of the substituents at the stereocenter, shows an 89percent reliability (correct for 54 of 61 examples).This rule is not reliable for primary alcohols that have an oxygen atom attached to the stereocenter; we excluded these alcohols from the tally above.Surprisingly, the sense of enantiopreference of PCL toward primary alcohols is opposit to its enantiopreference toward secondary alcohols.That is, the OH of secondary alcohols and the CH2OH of primary alcohols point in opposite directions.We suggest, however, that this opposite orientation does not imply a different position of the substituents in the active site of the lipase.Instead, PCL accommodates the extra CH2 in primary alcohols as a kink between the stereocenter and the oxygen which allows a similar position of the alcohols by increasing the diffrence in the size of the substituents but did not find a consistent increase in enantioselectivity.We suggest that high enantioselectivity toward primary alcohols requires not only a significant difference in the size of the substituents, but also control of the conformation along the C(1)-C(2) bond.

Acetolysis of 2-Aryl-1-methylpropyl Systems: Mechanism of the Formation of the Retained Product without Neighbouring Group Participation

threo-2--1-(13C)methylpropyl p-bromobenzenesulphonate (threo-(13C)1-OBs) has been solvolyzed in acetic acid to give rise to the retained threo-1-OAc which contains a small amount of threo-(13C)1-OAc accompanying no 13C-scrambling.At 75percent conversion, the isomerized erythro-1-OBs has been obtained along with the unchanged threo-1-OBs.Also, the erythro-1-OTs has been found at 50percent conversion in the presence of NaOTs.These stereochemical results indicate strongly that the acetate with the retained configuration accompanying no 13C-scrambling is formed via isomerization of the substrate by inversive anion exchange and a successive ks pathway with configurational inversion.Such a retained product was not detected in the acetolysis of threo-1-methyl-2-phenylpropyltoluene-p-sulphonate with no electron withdrawing substituent.

Cram's Rule for Radical Reactions

Addition of tris(trimethylsilyl)silyl radicals to chiral ketones 1 yields tert. carbon centered radicals 4 that give predominantly Cram products in hydrogen atom abstraction reactions.Analogous sec. acyloxyalkyl radicals undergo radical C,D- and C,C-bond forming reactions that also follow Cram's rule.

Studies on the Regioselectivities in the Oxidation of Simple Alkyl Aromatic Hydrocarbons by Molecular Oxygen

The products of the autoxidation of various simple alkyl aromatic hydrocarbons were reduced by LiAlH4, and the alcohols formed were determined by gas chromatography.In the cases of 2-phenylbutane, 3-phenylpentane, and 2-p-tolylbutane a considerable fragmentation of the intermediate tertiary alkoxy radicals was proved.On the basis of the analytical results relative reaction rates of the various C-H bonds in the hydrocarbons studied were calculated.It is shown that the attack at C-H bonds which are not activated by the aromatic nucleus cannot be neglected and may be of great importance for the kinetics of the oxidation of alkyl aromatic hydrocarbons.

Hydroboartion. 62. Monoisopinocampheylborane, an Excellent Chiral Hydroborating Agent for Trans-Disubstituted and Trisubstituted Alkenes. Evidenece for a Strong Steric Dependence in Such Asymmetric Hydroborations

Monoisopinocampheylborane (IpcBH2), the first monoalkylborane chiral hydroborating agent, is capable of reacting with olefins of varying stuctural and steric requiments to produce, in most cases, clean dialkylboranes.IpcBH2 achieves the asymmetric hydroboration of trans-disubstituted and trisubstituted olefins with exceptionally high asymmetric induction.The product alcohols, produced by oxidation of the intermediate organoboranes, exhibit enantiomeric purities in the range of 53-100percent ee and reveal the same absolute configuration.Enantiomeric purities of the products increase with increasing steric requirements of the alkyl or phenyl substituent in the trans-disubstituted or trisubstituted alkene.

SYNTHESIS OF (2S,3R,7RS)-STEGOBINONE (2,3-DIHYDRO-2,3,5-TRIMETHYL-6-(1-METHYL-2-OXOBUTYL)-4H-PYRAN-4-ONE) AND ITS (2R,3S,7RS)-ISOMER. THE PHEROMONE OF THE DRUGSTORE BEETLE

Reaction of acetaldehyde with the trianion of 4,6-dimethylnonane-3,5,7-trione followed by acidification yielded a stereoisomeric mixture of stegobinone, the pheromone of Stegobium paniceum L.Acylation of the dianion derived from 4-methylheptane-3,5-dione