Catalytic Cross-Coupling Reaction of Esters with Organoboron Compounds and Decarbonylative Reduction of Esters with HCOONH<sub>4</sub>: A New Route to Acyl Transition Metal Complexes through the Cleavage of Acyl−Oxygen Bonds in Esters
ketones. Acyl−alkyl coupling to dialkyl ketones is also achieved by the use of 9-alkyl-9-BBN in place of boronates. The Ru3(CO)12-catalyzed decarbonylative reduction of esters with ammonium formate (HCOONH4) leading to hydrocarbons is also described. No expected aldehydes are produced, and controlled experiments indicate that aldehydes are not intermediate for the transformation. A hydrosilane can also be
Palladium-Catalyzed Hydroarylation of 1,3-Dienes with Boronic Esters via Reductive Formation of π-Allyl Palladium Intermediates under Oxidative Conditions
作者:Longyan Liao、Matthew S. Sigman
DOI:10.1021/ja105010t
日期:2010.8.4
A palladium-catalyzed reductive cross-coupling of 1,3-dienes with boronicesters in which a pi-allyl Pd species is generated directly from a 1,3-diene via a Pd-catalyzed aerobicalcoholoxidation is reported. Both the scope of the process and the origin of a highly selective 1,2-addition are discussed.
A new approach to carbon–carbon bond formation: development of aerobic Pd-catalyzed reductive coupling reactions of organometallic reagents and styrenes
作者:Keith M. Gligorich、Yasumasa Iwai、Sarah A. Cummings、Matthew S. Sigman
DOI:10.1016/j.tet.2009.03.096
日期:2009.6
Alkenes are attractive starting materials for organic synthesis and the development of new selective functionalization reactions is desired. Previously, our laboratory discovered a unique Pd-catalyzed hydroalkoxylation reaction of styrenes containing a phenol. Based upon deuterium labeling experiments, a mechanism involving an aerobicalcoholoxidationcoupled to alkene functionalization was proposed
Asymmetric palladium-catalyzed hydroarylation of styrenes and dienes
作者:Susanne M. Podhajsky、Yasumasa Iwai、Amanda Cook-Sneathen、Matthew S. Sigman
DOI:10.1016/j.tet.2011.02.027
日期:2011.6
involved in the development of alkene hydro- and difunctionalization reactions, where β-hydride elimination can be controlled. We report herein the development of an asymmetric palladium-catalyzed hydroarylation, which yields diarylmethine products in up to 75% ee. Interestingly, a linear free energy relationship is observed between the steric bulk of the ligand within a certain range and the ee of the
烯烃是用于有机转化的理想且用途广泛的起始材料,也是众所周知的钯催化底物。通常,这些反应会通过β-氢化物消除形成新的烯烃产物。与这种情况相比,我们的实验室参与了烯烃加氢和双官能化反应的开发,其中可以控制 β-氢化物的消除。我们在此报告了不对称钯催化加氢芳基化的发展,该反应可产生高达 75% ee 的二芳基次甲基产物。有趣的是,在一定范围内的配体空间体积与反应的 ee 之间观察到线性自由能关系。
A Highly Selective and General Palladium Catalyst for the Oxidative Heck Reaction of Electronically Nonbiased Olefins
作者:Erik W. Werner、Matthew S. Sigman
DOI:10.1021/ja1060998
日期:2010.10.13
A general, highly selective oxidative Heck reaction is reported. The reaction is high-yielding under mild conditions without the need for base or high temperatures, and the selectivity is excellent, without the requirement for electronically biased olefins or other specific directing groups. A preliminary mechanistic investigation suggests that the unusually high selectivity may be due to the catalyst's sensitivity to C-H bond strength in the selectivity-determining beta-hydride elimination step.