Diastereoselective metal-catalyzed [4 + 2 + 2] carbocyclization reactions utilizing a rhodium N-heterocyclic carbene (NHC) complex: the first example of a rhodium NHC-catalyzed [m+n+o] carbocyclization
Ni‐Catalyzed Cyclization of Enynes and Alkynylboronates: Atom‐Economical Synthesis of Boryl‐1,4‐dienes
作者:Natalia Cabrera‐Lobera、M. Teresa Quirós、Elena Buñuel、Diego J. Cárdenas
DOI:10.1002/chem.201903405
日期:2019.11.18
We report a novel atom-economical Ni-catalyzed cyclization reaction of enynes with alkynylboronates. The reaction employs a non-expensive Ni salt, a phosphine-based ligand and easy-handling alkynylboronates as boron-carbon source. The reaction provides complex fused-bicyclic compounds containing borylated 1,4-cyclohexadienes in high yields in short reaction times, involving the formation of two C-C
Nickel-Catalyzed Reductive Cycloisomerization of Enynes with CO<sub>2</sub>
作者:Justin B. Diccianni、Tyler Heitmann、Tianning Diao
DOI:10.1021/acs.joc.7b01034
日期:2017.7.7
carboxylates from petroleum feedstock require a series of oxidation reactions. CO2 represents a cheap and sustainable, preoxidized C1 source. Herein, we describe a simple, selective, and mild procedure for the construction of (hetero)cyclic α,β-unsaturated carboxylic acids from 1,6- and 1,7-enyes and CO2. Terminal 1,7-enynes and stericallyhindered alkenes experience a change in regioselectivity and form
Selectivities in Nickel-Catalyzed Hydrocarboxylation of Enynes with Carbon Dioxide
作者:Tao Cao、Zheng Yang、Shengming Ma
DOI:10.1021/acscatal.7b00556
日期:2017.7.7
A three-component hydrocarboxylation of enynes with ZnEt2 and CO2 is realized. Highly selective cyclizative carboxylation of the C–C triple bond was observed. Preliminary mechanistic studies indicated both the concerted cyclometalation mechanism and the stepwise C═C bond-directed carboxylation were possible in this reaction.
Diastereoselective Intermolecular Rhodium-Catalyzed [4 + 2 + 2] Carbocyclization Reactions: Computational and Experimental Evidence for the Intermediacy of an Alternative Metallacycle Intermediate
作者:Mu-Hyun Baik、Erich W. Baum、Matthew C. Burland、P. Andrew Evans
DOI:10.1021/ja043521l
日期:2005.2.1
Intermolecular rhodium-catalyzed [m + n + o] reactions of 1,6-enynes and various pi-components (carbon monoxide, alkynes, 1,3-butadienes, etc.) provide an expeditious approach for the construction of polycyclic fragments that represent important synthons for target-directed synthesis. We present computational and experimental evidence for the existence of a previously undescribed reaction pathway for the rhodium-catalyzed [4 + 2 + 2] reaction involving a 1,6-enyne. This model clearly demonstrates the origin of the excellent diastereoselectivity in this type of reaction and the remarkable tolerance of both (E)- and (Z)-isomers within the 1,6-enyne, which is generally prone to competitive ene-cycloisomerization.