Enantioselective Cu-Catalyzed 1,4-Addition of Grignard Reagents to Cyclohexenone Using Taddol-Derived Phosphine-Phosphite Ligands and 2-Methyl-THF as a Solvent
Development of a Kilogram-Scale Process for the Enantioselective Synthesis of 3-Isopropenyl-cyclohexan-1-one via Rh/DTBM-SEGPHOS-Catalyzed Asymmetric Hayashi Addition Enabled by 1,3-Diol Additives
作者:Eric M. Simmons、Boguslaw Mudryk、Andrew G. Lee、Yuping Qiu、Thomas M. Razler、Yi Hsiao
DOI:10.1021/acs.oprd.7b00253
日期:2017.10.20
The development of a scalable process for the Rh-catalyZed asymmetric 1,4-addition of (isopropenyl)-pinacolboronate to 2-cyclohexen-1-one is reported. High-throughput ligand screening and initial optimization studies identified DTBM-SEGPHOS as an effective ligand along with a heptane/MeOH mixed solvent system. An inhibitory effect of the pinacol byproduct was identified, which could be mitigated by the addition of a 1,3-diol such as neopentyl glycol (npg). This process was demonstrated on 1 kg scale with 0.6 mol % Rh, producing (S)-1 in 82% yield and 99.6% ee, and was successfully scaled up at a vendor on 100 kg scale.
PHOTOLABILE PRO-FRAGRANCES
申请人:Henkel AG & Co. KGaA
公开号:US20180170849A1
公开(公告)日:2018-06-21
A method for producing photo-cleavable fragrance pre-cursors is described, which includes potential stereoselective method steps, agents containing the fragrance pre-cursors and the use of the fragrance pre-cursors for prolonging the scent impression in the agent and on surfaces treated with said agent.
Organo[2-(hydroxymethyl)phenyl]dimethylsilanes as Mild and Reproducible Agents for Rhodium-Catalyzed 1,4-Addition Reactions
achievement of the corresponding enantioselective transformations using the tetraorganosilicon reagents, providing the silicon-based approach to opticallyactiveketones and substituted piperidones that serve as synthetic intermediates of pharmaceuticals. A rhodium alkoxide species is suggested to be responsible for a transmetalation step on the basis of the observed kinetic resolution of a racemic chiral phenylsilane
reductase (BCR) as known from Thauera aromatica K172 and (ii) a modified β‐oxidation pathway yielding 3‐isopropylpimeloyl‐CoA analogously to benzoyl‐CoA degradation in Rhodopseudomonas palustris. Reference standards of all four diastereoisomers of 2‐hydroxy‐4‐isopropylcyclohexane‐1‐carboxylate as well as both enantiomers of 3‐isopropylpimelate were obtained by stereoselectivesyntheses via methyl 4‐isopr