Ni-Catalyzed Enantioselective Conjunctive Coupling with C(sp3) Electrophiles: A Radical-Ionic Mechanistic Dichotomy
摘要:
The catalytic enantioselective conjunctive coupling of C(sp(3)) electrophiles can be accomplished with Ni catalysis. The enantioselectivity of the reaction is dependent on reaction mechanism with many substrates able to engage in an asymmetric process with Pybox-Ni complexes, whereas other substrates provide racemic product mixtures. The link between substrate structure and selectivity is addressed.
Zirconium-Catalyzed Synthesis of Alkenylaminoboranes: From a Reliable Preparation of Alkenylboronates to a Direct Stereodivergent Access to Alkenyl Bromides
A simple procedure has been optimized for the preparation of alkenylaminoborane from alkynes using diisopropylaminoborane and HZrCp2Cl. Coupled with a magnesium-catalyzed dehydrogenation, it allowed for the use of air- and moisture-stable diisopropylamine. This synthesis has been extended to a one-pot sequence leading directly to bromoalkenes with controlled stereochemistry. As such, it provides an
Application of the Lithiation−Borylation Reaction to the Preparation of Enantioenriched Allylic Boron Reagents and Subsequent In Situ Conversion into 1,2,4-Trisubstituted Homoallylic Alcohols with Complete Control over All Elements of Stereochemistry
作者:Martin Althaus、Adeem Mahmood、José Ramón Suárez、Stephen P. Thomas、Varinder K. Aggarwal
DOI:10.1021/ja910593w
日期:2010.3.24
of aldehydes gave (Z)-anti-homoallylic alcohols in greater than 95:5 er and 99:1 dr. However, in the special case of the methyl-substituted lithiated carbamate, diamine-free conditions were required to achieve high selectivity. Reactions of sparteine-complexed lithiated carbamates with (Z)-alkenyl pinacol boronic esters and (E)-alkenyl neopentyl boronic esters gave (E)-syn- and (E)-anti-homoallylic
Hoppe 的锂化氨基甲酸酯与乙烯基硼烷和硼酸酯的反应得到烯丙基硼烷/硼酸酯,随后加入醛类为高对映体比率和非对映体比率的对映体富集的高烯丙醇提供了一条新途径。具体而言,sparteine 络合的锂化氨基甲酸酯与反式-链烯基-9-BBN 衍生物的反应,然后加入醛,以大于 95:5 er 和 99:1 dr 的形式生成 (Z)-抗高烯丙醇。然而,在甲基取代锂化氨基甲酸酯的特殊情况下,需要无二胺条件才能实现高选择性。sparteine 络合的锂化氨基甲酸酯与 (Z)-链烯基频哪醇硼酸酯和 (E)-链烯基新戊基硼酸酯的反应分别生成 (E)-syn- 和 (E)-anti-homoallylic 醇, 大于 96: 4 er 和 98:2 博士。在这些反应中,需要路易斯酸 (MgBr(2) 或 BF(3) x OEt(2)) 来促进 1,2-金属酸盐重排和中间烯丙基硼酸酯添加到醛中。该方法为三类高选择性高烯丙醇中的每一种提供了通用途径。
A Cu-based chiral catalyst enables convergent, highly enantioselective three-component assembly of alkenyl cyclopropylamines containing up to all three stereogenic centers.
METHOD FOR PREPARING ALKENYL AMINOBORANES AND THEIR DERIVATIVES, AND USES THEREOF
申请人:UNIVERSITE DE BORDEAUX
公开号:US20220396591A1
公开(公告)日:2022-12-15
Disclosed is a method for preparing alkenyl aminoboranes and their derivatives, and uses thereof. The method for preparing alkenyl aminoboranes includes contacting, preferably in a single synthesis step, a terminal alkyne, an aminoborane and a catalyst chosen from Schwartz's reagent (Cp2ZrHCl), dicyclohexylborane (HBCy), diisopinocamphenylborane (HBipc2) and 9-Borabicyclo(3.3.1)nonane (9-BBN).
Application of the Lithiation−Borylation Reaction to the Preparation of Enantioenriched Allylic Boron Reagents and Subsequent in Situ Conversion into 1,2,4-Trisubstituted Homoallylic Alcohols with Complete Control over All Elements of Stereochemistry
作者:Martin Althaus、Adeem Mahmood、José Ramón Suárez、Stephen P. Thomas、Varinder K. Aggarwal