Pd-Catalyzed Regioselective Decarboxylative/C–H α-Alkoxyalkenylation of Heterocycles Using α-Carboxyvinylethers
摘要:
A direct introduction of vinyl ethers into C-H bond of heterocycles is reported. For this purpose, decarboxylative direct C-H cross-coupling of 1,3-diazoles with alpha-carboxyvinyl ethers as coupling partners was achieved under Pd(0)/Cu(I) cooperative catalysis to produce various alpha-heteroarylated vinylethers. This methodology was applied to the innovative production of heteroarylated enolizable ketones and naturally occurring bis-oxa(thia)zoles.
Cyclopropanation of alkenes with metallocarbenes generated from monocarbonyl iodonium ylides
作者:Tristan Chidley、Graham K. Murphy
DOI:10.1039/c8ob02636j
日期:——
Reacting Wittigreagents and the hypervalent iodine reagent iodosotoluene, in the presence of 10 mol% Cu(tfacac)2 and 5 equiv. of alkene, results in a novel cyclopropanation reaction. The reagent combination is believed to generate a transient monocarbonyliodoniumylide (MCIY) in situ, which can be intercepted by the copper catalyst to give a metallocarbene. Both ester and ketone derived phosphoranes
A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, undermildconditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.
Methods for the synthesis of phenylacetaldehydes (oxidation, one-carbon chain extension) were compared by using the synthesis of 4-methoxyphenylacetaldehyde as a model example. Oxidations of 4-methoxyphenylethanol with activated DMSO (Swern oxidation) or manganese dioxide gave unsatisfactory results; whereas oxidation with 2-iodoxybenzoic acid (IBX) produced 4-methoxyphenylacetaldehyde in reasonable
Titanium-catalyzed highly stereoselective anti-Markovnikov intermolecular hydroalkoxylation of alkynes to prepare <i>Z</i>-enol ethers
作者:Yang Wang、Biao Ma、Yingning Mao、Zhihui Wang、Jinsong Peng、Chunxia Chen、Zhanyu Li
DOI:10.1039/d3ob01514a
日期:——
Enol ethers are essential synthetic frameworks and widely applied in organic synthesis; however, high regio- and stereo-selective access to enol ethers remains challenging. Herein, we report a titanium-catalyzed stereospecific anti-Markovnikov hydroalkoxylation reaction of alkynes for the synthesis of Z-enol ethers with excellent functional group tolerance and yields. Mechanistic studies showed that
Carbenoid versus Vinylogous Reactivity in Rhodium(II)-Stabilized Vinylcarbenoids
作者:Huw M. L. Davies、Baihua Hu、Elie Saikali、Paul R. Bruzinski
DOI:10.1021/jo00095a031
日期:1994.8
Rhodium(II)-stabilized vinylcarbenoid intermediates display electrophilic character at both the carbenoid site and the vinylogous position. The solvent and catalyst as well as the vinylcarbenoid structure have major effects on the regiochemical outcome of the reaction of vinylcarbenoids with alkenes and dienes. Reaction of vinylcarbenoids with vinyl ethers can lead to the formation of either cyclopropanes or cyclopentenes while reaction of vinylcarbenoids with cyclopentadiene can lead to the formation of either bicyclo[3.2.1]octadiene or bicyclo[2.2.1]heptene derivatives.