Air- and Light-Stable <i>S</i>-(Difluoromethyl)sulfonium Salts: <i>C</i>-Selective Electrophilic Difluoromethylation of β-Ketoesters and Malonates
作者:Sheng-Le Lu、Xin Li、Wen-Bing Qin、Jian-Jian Liu、Yi-Yong Huang、Henry N. C. Wong、Guo-Kai Liu
DOI:10.1021/acs.orglett.8b03067
日期:2018.11.2
Air- and light-stable electrophilic difluoromethylating reagents, S-(difluoromethyl)-S-phenyl-S-(2,4,6-trialkoxyphenyl) sulfonium salts were successfully developed, and the introduction of intramolecular hydrogen bonds plays a crucial role for the stabilities and reactivities of these reagents. C-selective difluoromethylation of a broad range of β-ketoesters and malonates proceeded smoothly under mild
Bench‐Stable
<i>S</i>
‐(Monofluoromethyl)sulfonium Salts: Highly Efficient
<i>C</i>
‐ and
<i>O</i>
‐Regioselective Monofluoromethylation of 1,3‐Dicarbonyl Compounds
作者:Wen‐Bing Qin、Jian‐Jian Liu、Zhongyan Huang、Xin Li、Wei Xiong、Jia‐Yi Chen、Guo‐Kai Liu
DOI:10.1002/ejoc.202000998
日期:2020.9.30
Novel bench‐stable S‐(monofluoromethyl)‐S‐phenyl‐S‐(2,4,6‐trialkoxyphenyl)sulfonium salts were readily prepared for C‐ and O‐regioselective monofluoromethylation of 1,3‐dicarbonyl compounds in good to excellent yields under mild reaction conditions.
Asymmetric Allylic Alkylation of β-Ketoesters via C–N Bond Cleavage of <i>N</i>-Allyl-<i>N</i>-methylaniline Derivatives Catalyzed by a Nickel–Diphosphine System
nickel-catalyzed AAA with allylicalcohols results in low enantioselectivity. On the basis of the kinetics using a catalyst system made of Ni(cod)2 and (S)-Tol-MeO-BIPHEP, and DFT calculations for the reaction pathway of the AAA reaction mediated by an isolated olefin-coordinated nickel–DPPF complex 4b, we propose a mechanism where protonation of the nitrogen atom of the coordinating allylic amine by β-ketoester
Highly C-selective difluoromethylation of β-ketoesters by using TMSCF<sub>2</sub>Br/lithium hydroxide/<i>N</i>,<i>N</i>,<i>N</i>-trimethylhexadecan-1-ammonium bromide
作者:Jiandong Wang、Etsuko Tokunaga、Norio Shibata
DOI:10.1039/c8cc05135f
日期:——
The highly C-selective difluoromethylation of β-ketoesters was achieved by combining TMSCF2Br/LiOH/N,N,N-trimethylhexadecan-1-ammonium bromide. Compared to other alkali metal salts or organicbases, lithiumhydroxide, which served as a difluorocarbene activator from TMSCF2Br, was crucial in the control of high C/O regioselectivity.
Asymmetric Allylic Alkylation of β-Ketoesters with Allylic Alcohols by a Nickel/Diphosphine Catalyst
作者:Yusuke Kita、Rahul D. Kavthe、Hiroaki Oda、Kazushi Mashima
DOI:10.1002/anie.201508757
日期:2016.1.18
Asymmetricallylicalkylation of β‐ketoesters with allylicalcohols catalyzed by [Ni(cod)2]/(S)‐H8‐BINAP was found to be a superior synthetic protocol for constructing quaternary chiral centers at the α‐position of β‐ketoesters. The reaction proceeded in high yield and with high enantioselectivity using various β‐ketoesters and allylicalcohols, without any additional activators. The versatility of