intramolecular substitutionreaction with alkoxide moiety occurs at the lithium alkylidene carbenoid center to give dihydrofurans. The reaction mechanism of this intramolecular substitutionreaction is studied by B3LYP density functional calculations with the 6-31+G(d) basis set, and the substitution is found to proceed in a concerted manner. This substitutionreaction is applied to the regioselective preparation
Air-Stable α-Diimine Nickel Precatalysts for the Hydrogenation of Hindered, Unactivated Alkenes
作者:Nadia G. Léonard、Paul J. Chirik
DOI:10.1021/acscatal.7b03909
日期:2018.1.5
isotopologues of the alkanes, signaling chain running processes that are competitive with productive hydrogenation. Stoichiometric studies, titration, and deuteriumlabeling experiments identified that the borane reagent served the dual role of reducing nickel(II) bis(carboxylate) to the previously reported nickel hydride dimer [(iPrDI)NiH]2 and increasing the observed hydrogenation activity. Performing the
空气稳定的双(辛酸镍(II)镍(II),Ni(O 2 CC 7 H 15)2和α-二亚胺配体,iPr DI或Cy ADI(iPr DI = [2,6- i Pr 2 -C 6 H ^ 3 N = C(CH 3)] 2,赛扬ADI = [C 6 H ^ 11 N = C(CH 3)] 2)与频哪醇硼烷(HBPin)生成用于氢化受阻,基本未官能化的烯烃的高活性催化剂。氢化了一系列的三和四取代的烯烃,并证明了以数克为单位的1-苯基-1-环己烯氢化的台式操作程序,代表了这种挑战性类别的镍催化氢化反应的催化剂活性和范围的进步。烯烃。用iPr DI用原位生成的镍催化剂对1,2-二甲基茚进行氘化可独家提供1,2- syn - d 2-二甲基茚满。使用环状三取代烯烃(例如1-甲基茚和甲基环己烯),在D 2的4 atm下用原位生成的镍催化剂进行氘化产生了烷烃的多个氘代同位素,这标志着与生产性氢化竞争的链运行
Designing a Planar Chiral Rhodium Indenyl Catalyst for Regio- and Enantioselective Allylic C–H Amidation
作者:Caitlin M. B. Farr、Amaan M. Kazerouni、Bohyun Park、Christopher D. Poff、Joonghee Won、Kimberly R. Sharp、Mu-Hyun Baik、Simon B. Blakey
DOI:10.1021/jacs.0c07305
日期:2020.8.12
Chiral variants of group IX Cp and Cp* catalysts are well established and catalyze a broad range of reactions with high levels of enantioselectivity. Enantiocontrol in these systems results from ligand design that focuses on appropriate steric blocking. Herein we report the development of a new planar chiral indenyl rhodium complex for enantioselectiveC-H functionalization catalysis. The ligand design
Efficient synthesis of 2- and 3-substituted indenes from 2-bromobenzyl bromide through an enolate alkylation/Cr(II)/Ni(II)-mediated carbonyl addition sequence
作者:Ronald L. Halterman、Chengian Zhu
DOI:10.1016/s0040-4039(99)01541-5
日期:1999.10
efficient new synthesis of 2- and 3-substituted indenes has been developed based on the nickel-catalyzed chromium(II)-promoted addition of aryl bromides to a tethered ketone carbonyl. Several tethered bromoaryl ketones were prepared through enolatealkylation of acyclic or cyclic ketones with 2-bromobenzyl bromide. Nozaki-Takai-Hiyama-Kishi closure of the resulting bromoaryl ketones followed by acid promoted
Extending the Substrate Scope in the Hydrogenation of Unfunctionalized Tetrasubstituted Olefins with Ir-P Stereogenic Aminophosphine–Oxazoline Catalysts
作者:Maria Biosca、Ernest Salomó、Pol de la Cruz-Sánchez、Antoni Riera、Xavier Verdaguer、Oscar Pàmies、Montserrat Diéguez
DOI:10.1021/acs.orglett.8b04084
日期:2019.2.1
MaxPHOX-type ligands have been successfully applied in the challenging asymmetrichydrogenation of tetrasubstitutedolefins under mild reaction conditions. Gratifyingly, these catalyst precursors are able to efficiently hydrogenate not only a range of indene derivatives (ee’s up to 96%) but also 1,2-dihydronapthalene derivatives and acyclic olefins (ee’s up to 99%), which both constitute the most challenging