cas 90499-41-5, Benzeneethanol, b-(1-methylethyl)-

Articles about 90499-41-5Total 9 be found

Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
supporting information
p. 14286 - 14294
(2020/09/15)

Visible-Light-Mediated Anti-Markovnikov Hydration of Olefins
Considering that stoichiometric borane and oxidant are required in the classical alkene anti-Markovnikov hydration process, it remains appealing to achieve the transformation in a catalytic protocol. Herein, a visible-light-mediated anti-Markovnikov addition of water to alkenes by using an organic photoredox catalyst in conjunction with a redox-active hydrogen atom donor was developed, which avoided the need for a transition-metal catalyst, stoichiometric borane, as well as oxidant. Both terminal and internal olefins are readily accommodated in this transformation to obtain corresponding primary and secondary alcohols in good yields with single regioselectivity. This procedure can be scaled up to gram scale with a 230 turnover number based on photocatalyst.
Hu, Xia,Zhang, Guoting,Bu, Faxiang,Lei, Aiwen
p. 1432 - 1437
(2017/08/09)

Impact of variation of the acyl group on the efficiency and selectivity of the lipase-mediated resolution of 2-phenylalkanols
By tuning the steric properties of the acyl group to control the efficiency and selectivity of the resolution, 2-phenyl-1-propanol 1a was prepared by lipase-catalysed hydrolysis using a short-chain acyl group, with E-values of up to 66 (ee up to 95%). 2-Phenylbutan-1-ol 1b was similarly resolved (up to 86% ee) using the optimised conditions, while the ester of the more sterically demanding 3-methyl-2-phenylbutan-1-ol 1c proved resistant to enzymatic hydrolysis under these conditions.
Foley, Aoife M.,Gavin, Declan P.,Joniec, Ilona,Maguire, Anita R.
p. 1144 - 1153
(2017/09/15)

Enecarbamates as Selective Substrates in Oxidations: Chiral-Auxiliary-Controlled Mode Selectivity and Diastereoselectivity in the [2+2] Cycloaddition and Ene Reaction of Singlet Oxygen and in the Epoxidation by DMD and mCPBA
The stereochemical course of the oxidation of chiral oxazolidinone-substituted enecarbamates has been studied for singlet oxygen (1O2), dimethyldioxirane (DMD), and m-chloroperbenzoic acid (mCPBA) by examining of the special structural and stereoelectronic features of the enecarbamates. Valuable mechanistic insight into these selective oxidations is gained. Whereas the R1 substituent on the chiral auxiliary is responsible for the steric shielding of the double bond and determines the sense of the π-facial diastereoselectivity, structural characteristic such as the Z/E configuration and the nature of the R 2 group on the double bond are responsible for the extent of the diastereoselectivity. Stereoelectronic steering by the vinylic nitrogen functionality controls the mode selectivity (ene reaction vs [2+2] cycloaddition) in the case of 1O2.
Adam, Waldemar,Bosio, Sara G.,Turro, Nicholas J.,Wolff, Barbara T.
p. 1704 - 1715
(2007/10/03)

Zr-Catalyzed Electrophilic Carbomagnesation of Aryl Olefins. Mechanism-Based Control of Zr-Mg Ligand Exchange
(Formula Presented) The first examples of efficient electrophilic Zr-catalyzed carbomagnesations are disclosed, where in contrast to previous catalytic carbomagnesations the alkyl moiety of the electrophile is transferred (vs that of the Grignard reagent)
De Armas, Judith,Hoveyda, Amir H.
p. 2097 - 2100
(2007/10/03)

A general approach towards 2-substituted 3-hydroxy propanoates; application to the synthesis of methyl tropinate
Enantiomerically pure R or S 2-substituted 3-hydroxy propanoates may be prepared by regioselective BF3 promoted opening of homochiral styrene oxide by lithium cyanocuprates followed by oxidative cleavage of the aromatic moiety with catalytic ru
Imogai, Hassan,Larcheveque, Marc
p. 965 - 972
(2007/10/03)

The Autoxidation of 1-Phenylalk-1-ynes. Proof of Oxirenes as Intermediates in the Oxidation of Acetylenes
In the autoxidations of 1-phenylprop-1-yne, 1-phenylbut-1-yne, and 1-phenyl-3-methylbut-1-yne a considerable attack at the CC triple bond takes place.Both products of the oxidative cleavage of the CC bond and products formed through the corresponding oxirenes were detected.The oxirenes rearrange via the isomeric ketocarbenes to ketenes, which yield the corresponding carboxylic acids or their esters.A part of the intermediate ketenes is oxidized with decarboxylation to lower ketones.All products were identified and quantitatively determined after LiAlH4 reduction to the corresponding alcohols.
Dao, Le Thi Anh,Blau, Karla,Pritzkow, Wilhelm,Schmidt-Renner, Wolfgang,Voerckel, Volkmar,Willecke, Lothar
p. 73 - 80
(2007/10/02)

NICKEL-CATALYZED STEREODIFFERENTIATING DISPLACEMENT REACTION BETWEEN PROCHIRAL 1-ALKENES AND OPTICALLY ACTIVE ORGANOALUMINIUM SOLVATES.
The displacement reaction between optically active AlBui3 solvates and vinylidene alkenes, in the presence of Ni(mesal)2, affords optically active trialkylalanes and hence, upon hydrolysis or oxidative procedure, alkanes or 1-alkanols.
Giacomelli, Giampaolo,Bertero, Luigi,Lardicci, Luciano
p. 883 - 886
(2007/10/02)

Stereochemistry of Aliphatic Carbocations, 15. Rearrangements in 2-Arylalkyl Systems
Phenyl shifts from secondary to primary carbon proceed with virtually complete inversion at the migration origin, regardless whether they are induced by solvolysis of the aryl sulfonate 25 or by deamination of the amines 12, 17, 26, and 43.Sequential rearrangements (Ph, CH3 and Ph, H) are likewise stereo- and regiospecific.These results strongly support the intervention of phenonium ions.In contrast, the competitive alkyl shifts (deamination only) from benzylic to primary carbon produce but a small excess of inversion (Me 27percent, Et 13percent, iPr 20percent, tBu 3percent).Obviously, benzyl cations are the predominant intermediates.
Kirmse, Wolfgang,Guenther, Bernd-Rainer,Loosen, Karin
p. 2140 - 2153
(2007/10/02)