Silylative Kinetic Resolution of Racemic 2,2‐Dialkyl 5‐ and 6‐Membered Cyclic Benzylic Alcohol Derivatives Catalyzed by Chiral Guanidine, (
<i>R</i>
)‐
<i>N</i>
‐Methylbenzoguanidine
作者:Shuhei Yoshimatsu、Kenya Nakata
DOI:10.1002/adsc.201900761
日期:2019.10.22
Efficient silylative kineticresolution of racemic 2,2‐dialkyl 5‐ and 6‐membered cyclic benzylic alcohols was achieved using diphenylmethylchlorosilane (Ph2MeSiCl) or phenyldimethylchlorosilane (PhMe2SiCl) as a silyl source catalyzed by chiral guanidine. The reaction could be applied to a broad range of 2,2‐dialkyl 1‐indanols with good s‐values, irrespective of the electronic nature of the substituent
RUTHENIUM COMPLEX AND PROCESS FOR PRODUCING TERT-ALKYL ALCOHOL THEREWITH
申请人:Nagoya Industrial Science Research Institute
公开号:EP1813621A1
公开(公告)日:2007-08-01
A tert-alkyl ketone, pinacolone was hydrogenated under pressurized hydrogen in the presence of a ruthenium complex (S)-1 and a base, and corresponding (S)-3,3,-dimethyl-2-butanol was thereby obtained in 100% yield and 97% ee.
Asymmetric Hydrogenation of <i>tert</i>-Alkyl Ketones
作者:Takeshi Ohkuma、Christian A. Sandoval、Rajagopal Srinivasan、Quinghong Lin、Yinmao Wei、Kilian Muñiz、Ryoji Noyori
DOI:10.1021/ja052071+
日期:2005.6.1
A combined system of RuCl2(tolbinap)(pica) and an alkaline or organic phosphazene base catalyzes asymmetric hydrogenation of sterically congested tert-alkyl ketones (TolBINAP = 2,2'-bis(di-4-tolylphosphino)-1,1'-binaphthyl, PICA = alpha-picolylamine). Hydrogenation with RuH(eta1-BH4)(tolbinap)(pica) does not require any strong base. Alcoholic solvents strongly affect the catalytic efficiency. The reaction proceeds smoothly in ethanol under 1-20 atm of H2 and at room temperature with a substrate to catalyst molar ratio of up to 100 000. Various aliphatic, aromatic, heteroaromatic, and olefinic tert-alkyl ketones are convertible to the corresponding chiral carbinols in high enantiomeric purity. Olefinic and heteroaromatic functions are left intact. Certain cyclic ketones are also usable. The mode of enantioface selection is consistent and predictable.
Enantioselective ester hydrolyses employing Rhizopus nigricans. A method of preparing and assigning the absolute stereochemistry of cyclic alcohols