Scope and Mechanism of the Pt-Catalyzed Enantioselective Diboration of Monosubstituted Alkenes
作者:John R. Coombs、Fredrik Haeffner、Laura T. Kliman、James P. Morken
DOI:10.1021/ja4041016
日期:2013.7.31
The Pt-catalyzed enantioselective diboration of terminal alkenes can be accomplished in an enantioselective fashion in the presence of chiral phosphonite ligands. Optimal procedures and the substrate scope of this transformation are fully investigated. Reaction progress kinetic analysis and kinetic isotope effects suggest that the stereodefining step in the catalytic cycle is olefin migratory insertion
Iridium-Catalyzed Enantioselective Hydrogenation of Alkenylboronic Esters
作者:Adnan Ganić、Andreas Pfaltz
DOI:10.1002/chem.201200246
日期:2012.5.29
iridium complex derived from a phosphino–imidazoline ligand is a highly efficient catalyst for the asymmetric hydrogenation of terminal vinyl boronic esters (see scheme). On the other hand, trisubstituted alkenyl‐boronates can be reduced with high activity and good to excellent enantioselectivity employing a pyridine–phosphinite ligand.
Base-controlled highly selective synthesis of alkyl 1,2-bis(boronates) or 1,1,2-tris(boronates) from terminal alkynes
作者:Guoliang Gao、Jianxiang Yan、Kai Yang、Fener Chen、Qiuling Song
DOI:10.1039/c7gc01161j
日期:——
highly regioselective synthesis of alkyl 1,2-bis(boronates) or 1,1,2-tris(boronates) from various terminalalkynes has been disclosed. These reactions are efficient, practical and mild with good regioselectivity, excellent functional group tolerance as well as good scalability, which provide general and complementary methods to access multiborylated alkanes from various terminalalkynes.
Selective Coupling of 1,2‐Bis‐Boronic Esters at the more Substituted Site through Visible‐Light Activation of Electron Donor–Acceptor Complexes
作者:Hui Wang、Jingjing Wu、Adam Noble、Varinder K. Aggarwal
DOI:10.1002/anie.202202061
日期:2022.4.25
monofunctionalization of 1,2-bis-boronic esters was achieved by using a catalyst-free photoinduced coupling with (hetero)aryl nitriles. The reaction proceeds throughelectrondonor–acceptor (EDA) complex-driven deboronation and radical 1,2-boron shift, giving β-aryl primary boronicester products. The reaction also works with primary, secondary, and tertiary boronicesters.
Selective, Transition Metal‐free 1,2‐Diboration of Alkyl Halides, Tosylates, and Alcohols
作者:Mingming Huang、Jiefeng Hu、Shasha Shi、Alexandra Friedrich、Johannes Krebs、Stephen A. Westcott、Udo Radius、Todd B. Marder
DOI:10.1002/chem.202200480
日期:2022.4.27
simple and efficient strategy to access alkyl 1,2-bis(boronate esters) via regio- and diastereoselective diboration of readily available secondary and tertiary alkylhalides (Br, Cl, I), tosylates, and alcohols was developed. The use of KI and DMA is critical to the methodology, which circumvents the regio- and diastereoselectivity problems. The transformation showed a broad substrate scope (75 examples)
开发了一种无过渡金属、简单且有效的策略,通过对容易获得的仲和叔烷基卤化物(Br、Cl、I)、甲苯磺酸酯和醇进行区域和非对映选择性二硼化来获得烷基 1,2-双(硼酸酯) 。 KI 和 DMA 的使用对该方法至关重要,它可以避免区域选择性和非对映选择性问题。该转化显示了广泛的底物范围(75 个实例)以及天然产物后期修饰的实用性。