作者:Qiang-Qiang Li、Zaher Shah、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1021/acs.joc.7b02720
日期:2018.1.5
A base-promoted transition metal-free approach to substituted alkenes using alcohols under aerobic conditions using air as the inexpensive and clean oxidant is described. Aldehydes are relatively difficult to handle compared to corresponding alcohols due to their volatility and penchant to polymerize and autoxidize. Wittig ylides are easily oxidized to aldehydes and consequently form homo-olefination
Stereospecific synthesis of (E)-alkenylpyridines via α-silyl carbanion
作者:Takeo Konakahara、Yukio Takagi
DOI:10.1016/s0040-4039(00)71490-0
日期:1980.1
(E)-2-Alkenylpyridines were stereospecifically prepared from 2-(trimethylsilylmethyl)pyridine and the corresponding (E)-aldimines of anilines by an analogous reaction to the Peterson reaction.
Ruthenium-Mediated Regio- and Stereoselective Alkenylation of Pyridine
作者:Masahiro Murakami、Seiji Hori
DOI:10.1021/ja029829z
日期:2003.4.1
A novel alkenylation reaction of pyridine is developed. Heating a cationic ruthenium vinylidene complex [CpRu(=C=CHR)(PPh(3))(2)]PF(6) in pyridine at 100-125 degrees C for 24 h affords (E)-2-alkenylpyridine. Initially, pyridine coordinates to ruthenium by displacement of one of the phosphine ligands. Then, [2 + 2] heterocycloaddition occurs to form a four-membered ruthenacyclic complex. Deprotonation of the beta-hydrogen affords a neutral pi-azaallyl complex. Protonolysis furnishes the product. As a result, a vinylidene group is inserted into the alpha C-H bond of pyridine. The alkenylation reaction is made catalytic in ruthenium by the use of (alkyn-1-yl)silane as the vinylidene source. Treatment of (alkyn-1-yl)trimethylsilane with pyridine in the presence of a cationic ruthenium complex [CpRu(PPh(3))(2)]PF(6) affords the corresponding (E)-2-alkenylpyridine in good yield in a regio- and stereoselective manner.
Ruthenium-Catalyzed Arylation of 2-Alkenylpyridines with Aryl Bromides: Alternative <i>E,Z</i>-Selectivity to Mizoroki−Heck Reaction
作者:Shuichi Oi、Kaori Sakai、Yoshio Inoue
DOI:10.1021/ol051654l
日期:2005.9.1
[Graphics]Regio- and stereoselective arylation of 2-alkenylpyridines with aryl bromides is catalyzed by specific Ru(II)-phosphine complexes affording beta-arylated (Z)-2-alkenylpyridines, in which the aryl moiety is introduced cis to the pyridyl group. This geometrical selectivity is in sharp contrast to the Mizoroki-Heck reaction.
KONAKAHARA TAKEO; TAKAGI YUKIO, SYNTHESIS, 1979, NO 3, 192-194