An efficient and general method for the chemoselective synthesis of unsymmetrical gem‐diborylalkanes is reported. This method is based on a late‐stage desymmetrization through nucleophilic “trifluorination”, providing chiral gem‐diborylalkanes bearing a trifluoroborate group. The reaction offers a highly modular and diastereoselective approach towards the synthesis of gem‐diborylcyclopropanes. The
C–O Functionalization of α-Oxyboronates: A Deoxygenative <i>gem</i>-Diborylation and <i>gem</i>-Silylborylation of Aldehydes and Ketones
作者:Lu Wang、Tao Zhang、Wei Sun、Zeyu He、Chungu Xia、Yu Lan、Chao Liu
DOI:10.1021/jacs.7b02518
日期:2017.4.12
the success of this transformation is the base-promoted C-O bond borylation or silylation of the generated α-oxyboronates. Experimental and theoretical studies exhibit that the C-O bond functionalization proceeds via an intramolecular five-membered transition-state (9-ts) boryl migration followed by a 1,2-metalate rearrangement with OBpin as a leavinggroup. The transformation occurs with an inversion
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
The direct, stereospecific amination of alkylboronic and borinic esters can be conducted by treatment of the organoboron compound with methoxyamine and potassium tert-butoxide. In addition to being stereospecific, this process also enables the direct amination of tertiary boronic esters in an efficient fashion.
ZnMe<sub>2</sub>-Mediated, Direct Alkylation of Electron-Deficient N-Heteroarenes with 1,1-Diborylalkanes: Scope and Mechanism
作者:Woohyun Jo、Seung-yeol Baek、Chiwon Hwang、Joon Heo、Mu-Hyun Baik、Seung Hwan Cho
DOI:10.1021/jacs.0c06827
日期:2020.7.29
of electron-deficient N-heteroarenes is, in principle, a powerful and efficient way of accessing alkylated N-heteroarenes that are important core structures of many biologically active compounds and pharmaceutical agents. Herein, we report a ZnMe2-promoted, direct C2- or C4-selective primary and secondary alkylation of pyridines and quinolines using 1,1-diborylalkanes as alkylation sources. While substituted