Practical Solvent-Free Microwave-Assisted Hydroboration of Alkynes
作者:Julia Altarejos、David Sucunza、Juan J. Vaquero、Javier Carreras
DOI:10.1002/ejoc.202000110
日期:2020.5.29
A general method for solvent‐free hydroboration of alkynes has been developed by microwave irradiation, to get (E )‐alkenyl boronates. Several functionalizations in the C–B bond can be performed sequentially without the purification of the intermediates.
Highly Selective Methods for Synthesis of Internal (α-) Vinylboronates through Efficient NHC–Cu-Catalyzed Hydroboration of Terminal Alkynes. Utility in Chemical Synthesis and Mechanistic Basis for Selectivity
作者:Hwanjong Jang、Adil R. Zhugralin、Yunmi Lee、Amir H. Hoveyda
DOI:10.1021/ja2007643
日期:2011.5.25
procedures (1 mol % catalyst loading). Mechanistic studies are presented, indicating that α selectivity arises from the structural and electronic attributes of the NHC ligands and the alkyne substrates. Consistent with suggested hypotheses, catalyticreactions with a Cu complex, derived from an N-adamantyl-substituted imidazolinium salt, afford high β selectivity with the same class of substrates and under
N‐heterocyclic carbene‐cappedcyclodextrin (ICyD) ligands, α‐ICyD and β‐ICyD derived from α‐ and β‐cyclodextrin, respectively give opposite regioselectivities in a copper‐catalyzed hydroboration. The site‐selectivity results from two different mechanisms: the conventional parallel one and a new orthogonal mechanism. The shape of the cavity was shown not only to induce a regioselectivity switch but
Stereoselective Synthesis of Vinylboronates by Rh‐Catalyzed Borylation of Stereoisomeric Mixtures
作者:Shenhuan Li、Jie Li、Tianlai Xia、Wanxiang Zhao
DOI:10.1002/cjoc.201800575
日期:2019.5
The stereoselective preparation of vinylboronates via rhodium‐catalyzed borylation of E/Z mixtures of vinyl actetates is described, and this method was also extended to synthesis of vinyldiboronates. These transformations feature high functional group compatibility and mild reaction conditions. Control experiments support a mechanism that involved a Rh‐catalyzed borylation‐isomerization sequence. The