640291-86-7Relevant academic research and scientific papers
Tandem Iridium Catalysis as a General Strategy for Atroposelective Construction of Axially Chiral Styrenes
He, Ying,Liu, Peng,Min, Xiao-Long,Qi, Xiaotian,Wang, Jie,Yi, Wenbin
supporting information, p. 10686 - 10694 (2021/07/26)
Axially chiral styrenes are of great interest since they may serve as a class of novel chiral ligands in asymmetric synthesis. However, only recently have strategies been developed for their enantioselective preparation. Thus, the development of novel and efficient methodologies is highly desirable. Herein, we reported the first tandem iridium catalysis as a general strategy for the synthesis of axially chiral styrenes enabled by Asymmetric Allylic Substitution-Isomerization (AASI) using cinnamyl carbonate analogues as electrophiles and naphthols as nucleophiles. In this approach, axially chiral styrenes were generated through two independent iridium-catalytic cycles: iridium-catalyzed asymmetric allylic substitution and in situ isomerization via stereospecific 1,3-hydride transfer catalyzed by the same iridium catalyst. Both experimental and computational studies demonstrated that the isomerization proceeded by iridium-catalyzed benzylic C-H bond oxidative addition, followed by terminal C-H reductive elimination. Amid the central-to-axial chirality transfer, the hydroxyl of naphthol plays a crucial role in ensuring the stereospecificity by coordinating with the Ir(I) center. The process accommodated broad functional group compatibility. The products were generated in excellent yields with excellent to high enantioselectivities, which could be transformed to various axially chiral molecules.
A highly enantio- and diastereoselective molybdenum-catalyzed asymmetric allylic alkylation of cyanoesters
Trost, Barry M.,Miller, John R.,Hoffman Jr., Christopher M.
, p. 8165 - 8167 (2011/07/08)
An efficient molybdenum-catalyzed asymmetric allylic alkylation (Mo-AAA) of cyanoester nucleophiles is reported. A number of highly functionalized branched cyanoesters containing a quaternary carbon stereocenter with a vicinal tertiary stereocenter are obtained. This method generates a number of functionalized cyanoesters in excellent yield and chemoselectivity in good to excellent diastereoselectivity and enantioselectivity.
Enantioselective iridium-catalyzed allylic amination of ammonia and convenient ammonia surrogates
Pouy, Mark J.,Leitner, Andreas,Weix, Daniel J.,Ueno, Satoshi,Hartwig, John F.
, p. 3949 - 3952 (2008/02/11)
Iridium-catalyzed, asymmetric allylation of ammonia as a nucleophile occurs with stereoselectivity to form a symmetric dialiylamine, and related allylation of the inexpensive ammonia equivalent potassium trifluoroacetamide or the highly reactive ammonia equivalent lithium ditert-butyliminodicarboxylate forms a range of conveniently protected, primary, a-branched allylic amines in high yields, high branched-to-linear regioselectivities, and high enantiomeric excess. The reactions of ammonia equivalents were conducted with a catalyst generated from a phosphoramidite containing a single stereochemical element.
