Iridium-catalyzed diborylation of benzylic C–H bonds directed by a hydrosilyl group: synthesis of 1,1-benzyldiboronate esters
作者:Seung Hwan Cho、John F. Hartwig
DOI:10.1039/c3sc52824c
日期:——
We describe a regioselective diborylation of primary benzylic CâH bonds catalyzed by [Ir(COD)OMe]2 and 4,4â²-di-tert-butyl-2,2â²-bipyridine (dtbpy). The hydrosilyl group acts as a traceless directing group, providing access to a range of 1,1-benzyldiboronate esters in good yields. Transformations of the 1,1-benzyldiboronate ester products include chemoselective SuzukiâMiyaura cross-couplings and synthesis of tetrasubstituted alkenyl boronate esters.
Diversity-Oriented Synthesis of Tamoxifen-type Tetrasubstituted Olefins
作者:Kenichiro Itami、Toshiyuki Kamei、Jun-ichi Yoshida
DOI:10.1021/ja037566i
日期:2003.12.1
A general synthetic scheme for tamoxifen-typetetrasubstitutedolefins based on the novel Cu-catalyzed carbomagnesation acrossalkynyl(2-pyridyl)silane has been developed. A wide array of electronically and structurally diverse tetrasubstitutedolefins can be prepared in a regiocontrolled, stereocontrolled, and diversity-oriented manner. Noteworthy features are that (i) the three aryl groups, which
已经开发了基于新型 Cu 催化的炔基(2-吡啶基)硅烷碳镁化反应的他莫昔芬型四取代烯烃的一般合成方案。可以以区域控制、立体控制和面向多样性的方式制备各种电子和结构不同的四取代烯烃。值得注意的特征是 (i) 被认为对抗雌激素活性很重要(必不可少)的三个芳基可以随意变化,因为它们都源于容易获得的芳基碘化物,以及 (ii) 任何立体和原则上,区域异构体可以通过简单地改变芳基碘化物的应用顺序来制备。
Opportune<i>gem</i>-Silylborylation of Carbonyl Compounds: A Modular and Stereocontrolled Entry to Tetrasubstituted Olefins
作者:Enrico La Cascia、Ana B. Cuenca、Elena Fernández
DOI:10.1002/chem.201604782
日期:2016.12.23
An easy access to highly versatile gem‐silylboronate synthons is achieved by means of a new olefination reagent, HC(Bpin)2(SiMe3). Subsequent silicon or boron‐based selectivefunctionalization allows for the modular and stereocontrolled synthesis of all‐carbon tetrasubstituted alkenes. A particular attraction of this approach is the iododesilylation reaction, which becomes a pivotal tool for C−Si functionalization
Stereoselective Synthesis of Trisubstituted Vinylboronates from Ketone Enolates Triggered by 1,3‐Metalate Rearrangement of Lithium Enolates
作者:Yue Hu、Wei Sun、Tao Zhang、Nuo Xu、Jianeng Xu、Yu Lan、Chao Liu
DOI:10.1002/anie.201909235
日期:2019.10.28
unprecedented stereoselectivesynthesis of trisubstituted vinylboronates is reported to proceed by direct borylation of lithium ketone enolates under transition-metal-free conditions. The stereospecific C-O borylation of lithium enolates was triggered by a carbonyl-induced 1,3-metalate rearrangement via a C-bound boron enolate. DFT calculations and control experiments revealed that the stereoselectivity is controlled