Regio- and Diastereoselective Access to 4-Imidazolidinones via an Aza-Mannich Initiated Cyclization of Sulfamate-Derived Cyclic Imines with α-Halo Hydroxamates
An efficient regio- and diastereoselective cyclization of sulfamate-derived cyclic imines with unsubstituted or monosubstituted α-halo hydroxamates is developed under mild conditions. This reaction proceeds smoothly under transition-metal-free conditions via a domino aza-Mannich addition/intramolecular nucleophilic substitution sequence, providing a convenient route to access 2-monosubstituted and
Allylboration of Ketones and Imines with a Highly Reactive Bifunctional Allyl Pinacolatoboronate Reagent
作者:Jiaming Liu、Xinbo Tong、Ming Chen
DOI:10.1021/acs.joc.9b03222
日期:2020.4.17
Allylboration of ketones and imines with a bifunctional allylboron reagent is reported. Addition of the bifunctional allylboronate to a broad scope of ketones gave tertiary alcohols in excellent yields at ambient temperature without any catalyst or additive. Allylboration of cyclic aldimines also proceeded to give allylated products in good yields under the same reaction conditions. The allylsilane
Base-Free Conditions for Rhodium-Catalyzed Asymmetric Arylation To Produce Stereochemically Labile α-Aryl Ketones
作者:Xiaowei Dou、Yixin Lu、Tamio Hayashi
DOI:10.1002/anie.201601709
日期:2016.6.1
The asymmetric arylation of 2,2‐dialkyl cyclopent‐4‐ene‐1,3‐diones with aryl boronic acids was found to be efficiently catalyzed by a chiral diene–rhodium μ‐chloro dimer, [RhCl((R)‐diene*)}2], in the absence of bases in toluene/H2O to give 2,2‐dialkyl 4‐aryl cyclopentane‐1,3‐diones in high yields with high enantioselectivity. Such compounds can not be obtained with high enantiomeric purity under the
发现2,2-二烷基环戊-4-烯-1,3-二酮与芳基硼酸的不对称芳构化可以通过手性二烯-铑μ-氯二聚体[RhCl((R)-二烯*)} 2 ],在甲苯/ H 2 O中不存在碱的情况下,以高收率和高对映选择性得到2,2-二烷基4-芳基环戊烷-1,3-二酮。在用于铑催化的不对称芳基化的标准基本条件下,无法以高对映体纯度获得此类化合物,因为α-芳基酮产品在基本条件下会发生外消旋作用。
Spiro indane-based phosphine–oxazoline ligands for palladium-catalyzed asymmetric arylation of cyclic N-sulfonyl imines
作者:Zhongxuan Qiu、Yanshun Li、Zhenqing Zhang、Dawei Teng
DOI:10.1007/s11243-019-00329-z
日期:2019.10
Palladium complexes of indane-based phosphine–oxazoline ligands with a spirocarbon stereogenic center were examined for asymmetric addition of arylboronic acids to cyclic N-sulfonyl imines. Excellent reaction activities (up to 99% yield) and enantioselectivities (up to 99% ee) were obtained with a broad scope of substrate.
A series of chiral phosphine‐imine ligands were synthesized starting with α‐amino acids and examined for palladium‐catalyzed asymmetric addition of arylboronic acids to cyclic N‐sulfonylimines. High catalytic activities (up to 99% yield) and high enantioselectivities (up to 98% ee) were achieved for cyclic N‐sulfonyl aldimines and ketimines with five and six‐membered ring structures.