Palladium-Catalyzed Cross-Coupling of <i>gem</i>-Bis(boronates) with Aryl Halides: An Alternative To Access Quaternary α-Aryl Aldehydes
作者:Purui Zheng、Yujie Zhai、Xiaoming Zhao、Tao XU
DOI:10.1021/acs.orglett.8b03560
日期:2019.1.18
The compounds with a quaternary α-aryl aldehyde skeleton are important units in organic chemistry. Previously, the aryl group and carbonyl group are introduced in a stepwise manner. Herein, a novel route is developed to construct the quaternary α-aryl aldehydes with gem-bis(boronates) as precursors, in which the two groups are installed simultaneously. The gem-bis(boronates) are readily available from
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
perfluoroalkyl radical addition. It is shown that radical 1,2- and 1,4-boron migrations to provide geminal and 1,3-bisborylalkanes are efficient transformations. The 1,5-boron migration in the homologous series leading to 1,4-bisborylalkanes is also occurring, albeit with lower efficiency. Experimental results are supported by DFT calculations which also reveal the corresponding 1,3-boron migration in such
We have developed an efficient method for synthesizing chiral 1,2-bis(boronic) esters bearing non-adjacent, acyclic 1,3-stereocenters. Notably, a novel activation mode for gem-diborylalkanes in asymmetric catalysis has been uncovered, avoiding two potential side-products encountered when using classical conditions. This innovative approach exhibits excellent chemo-, regio-, enantio- and diastereoselectivity
Formal Carbon Insertion of <i>N-</i>Tosylhydrazone into B–B and B–Si Bonds: <i>gem</i>-Diborylation and <i>gem</i>-Silylborylation of sp<sup>3</sup> Carbon
作者:Huan Li、Xianghang Shangguan、Zhikun Zhang、Shan Huang、Yan Zhang、Jianbo Wang
DOI:10.1021/ol403338s
日期:2014.1.17
A convenient method is developed to synthesize 1,1-diboronates from the corresponding N-tosylhydrazones. This method is also applicable to synthesize 1-silyl-1-boron compounds. Meanwhile, derivatization and consecutive Pd-catalyzed cross-coupling reactions with 1,1-boronates were explored, demonstrating the synthetic potential of 1,1-diboronates.