hydrogenation of unfunctionalized aryl-substituted olefins with iridium-phosphanyldihydrooxazole complexes 1 (see reaction scheme). The anion of the complex-for example, hexafluorophosphate or tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BARF- )-has a remarkable effect on the reactivity and longevity of the catalyst.
Enantioselective Nickel-Catalyzed <i>anti</i>-Carbometallative Cyclizations of Alkynyl Electrophiles Enabled by Reversible Alkenylnickel <i>E</i>/<i>Z</i> Isomerization
作者:Christopher Clarke、Celia A. Incerti-Pradillos、Hon Wai Lam
DOI:10.1021/jacs.6b04206
日期:2016.7.6
Nickel-catalyzedadditions of arylboronic acids to alkynes, followed by enantioselective cyclizations of the alkenylnickel species onto tethered ketones or enones, are reported. These reactions are reliant upon the formal anti-carbonickelation of the alkyne, which is postulated to occur by the reversible E/Z isomerization of an alkenylnickel species.
Cobalt-catalysed synthesis of highly substituted styrene derivatives via arylzincation of alkynes
作者:Martin Corpet、Corinne Gosmini
DOI:10.1039/c2cc36676b
日期:——
A new two-step procedure was developed by carbozincation of internal and terminal alkynes to synthesise highly functionalised vinylzinc bromides. Various tri and tetrasubstituted alkenes were prepared in moderate to good yields under mild reaction conditions in a stereo-selective manner. This methodology represents an interesting alternative to previously known methods.
Addition of arylmagnesium bromides to aryl(alkyl)acetylenes proceeded in the presence of an iron catalyst and a N-heterocyclic carbene ligand to give high yields of the corresponding alkenylmagnesium reagents, which were transformed into tetrasubstituted alkenes by subsequent treatment with electrophiles. [reaction: see text]
Versatile Relay and Cooperative Palladium(0)<i>N</i>-Heterocyclic Carbene/Copper(I)<i>N</i>-Heterocyclic Carbene Catalysis for the Synthesis of Tri- and Tetrasubstituted Alkenes
作者:Mathieu Lesieur、Yannick D. Bidal、Faïma Lazreg、Fady Nahra、Catherine S. J. Cazin
DOI:10.1002/cctc.201500268
日期:2015.7.13
Two new and efficient dual catalytic procedures for the synthesis of tri‐ and tetrasubstituted alkenes using aryl bromides and chlorides are reported. The formation of these vinyl arenes occurs independently in a one‐pot relay and a one‐pot cooperative procedure using well‐defined Pd and Cu N‐heterocycliccarbene (NHC) complexes. Mechanistic studies were performed to elucidate the key role of the solvent