Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol
作者:Colton R. Davis、Irungu K. Luvaga、Joseph M. Ready
DOI:10.1021/jacs.1c01242
日期:2021.4.7
Alkenyl boronates add to Ir(π-allyl) intermediates with high enantioselectivity. A 1,2-metalate shift forms a second C–C bond and sets a 1,3-stereochemical relationship. The three-component coupling provides tertiary boronic esters that can undergo multiple additional functionalizations. An extension to trisubstituted olefins sets three contiguous stereocenters.
Stereodivergent Access to Trisubstituted Alkenylboronate Esters through Alkene Isomerization
作者:Lucas Segura、Itai Massad、Masamichi Ogasawara、Ilan Marek
DOI:10.1021/acs.orglett.1c03513
日期:2021.12.3
We report an efficient method for the preparation of synthetically valuable trisubstituted alkenylboronate esters through alkene isomerization of their readily available 1,1-disubstituted regioisomeric counterparts. Either stereoisomer of the target alkenylboronate motif can be obtained at will from the same starting material by employing different isomerization catalysts.
Copper-catalyzed regioselective hydroboration of terminal alkynes in aqueous medium
作者:Zi-Jian Yao、Shibin Hong、Wei Zhang、Mengyan Liu、Wei Deng
DOI:10.1016/j.tetlet.2016.01.049
日期:2016.2
A mild and environment-friendly copper-catalyzed hydroboration of terminalalkynes in aqueous medium was reported. Regioselectivity control was achieved in the presence of cyclodextrin–bispyridine ligand (CD-1). This protocol was successfully applied to inactivated terminalalkynes. Moreover, the ligand was recovered and reused without any loss of activity over five cycles.
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
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.