Transition metal-catalyzed dehydrogenation is a clean oxidation method requiring no additional oxidants. We have accomplished a heterogeneous Pd/C-catalyzed aqueous dehydrogenation of 1,4-cyclohexadienes and cyclohexenes to give the corresponding highly-functionalized arenes. Furthermore, various arenes could be efficiently constructed in a one-pot manner via a Diels–Alder reaction and the following
Versatile C(sp<sup>2</sup>)−C(sp<sup>3</sup>) Ligand Couplings of Sulfoxides for the Enantioselective Synthesis of Diarylalkanes
作者:William M. Dean、Mindaugas Šiaučiulis、Thomas E. Storr、William Lewis、Robert A. Stockman
DOI:10.1002/anie.201602264
日期:2016.8.16
The reaction of chiral (hetero)aryl benzyl sulfoxides with Grignard reagents affords enantiomerically pure diarylalkanes in up to 98 % yield and greater than 99.5 % enantiomeric excess. This ligand coupling reaction is tolerant to multiple substitution patterns and provides access to diverse areas of chemical space in three operationally simple steps from commercially available reagents. This strategy
Iron-Facilitated Direct Oxidative C−H Transformation of Allylarenes or Alkenes to Alkenyl Nitriles
作者:Chong Qin、Ning Jiao
DOI:10.1021/ja1070202
日期:2010.11.17
facilitated by an inexpensive homogeneous iron catalyst. Three C-H bondcleavages occur under the mild conditions during this process. Mechanistic studies indicate that the cleavage of the allyl C(sp(3))-Hbond is involved in the rate-determining step. This observation may provide an opportunity to achieve C(sp(3))-H functionalization catalyzed by an iron catalyst.
Mild Isomerization of Conjugated Dienes Using Co-Mediated Hydrogen Atom Transfer
作者:Kyle R. Delgado、Dustin D. Youmans、Steven T. Diver
DOI:10.1021/acs.orglett.9b04594
日期:2020.1.17
A mild and high yielding rearrangement of 1,3-disubstituted-1,3-dienes to 1,1,4-trisubstituted-1,3-dienes using a cobaloxime catalyst and a silane cocatalyst is reported. Chiral centers near the conjugated diene were not racemized. Deuterium labeling studies are consistent with a hydrogen atom transfer mechanism, and radical intermediates were found to be accessible due to the observed ring opening
Cobalt-Catalyzed Migration Isomerization of Dienes
作者:Jiajin Zhao、Guoxiong Xu、Xue Wang、Jiren Liu、Xiang Ren、Xin Hong、Zhan Lu
DOI:10.1021/acs.orglett.2c01701
日期:2022.7.1
multipositional isomerization of conjugateddienes has been reported for the first time using an 8-oxazoline iminoquinoline ligand. This reaction is operationally simple and atom-economical using readily available starting materials with an E/Z mixture to access disubstituted 1,3-dienes with excellent yields and good E,E stereoselectivity. The mechanism via alkene insertion of cobalt hydride species and β-H elimination