Chemo- and Regioselective Synthesis of Acyl-Cyclohexenes by a Tandem Acceptorless Dehydrogenation-[1,5]-Hydride Shift Cascade
作者:Lewis B. Smith、Roly J. Armstrong、Daniel Matheau-Raven、Timothy J. Donohoe
DOI:10.1021/jacs.9b12296
日期:2020.2.5
acceptorless dehydrogenation of the diol followed by a redox-neutral cascade process, which is independent of the iridium catalyst. Deuteriumlabelingstudies established that the key step of this cascade involves a novel base-mediated [1,5]-hydride shift. The cyclohexenyl ketone products could readily be cleaved under mildly acidic conditions to access a range of valuable substituted cyclohexene derivatives
描述了一种从五甲基苯乙酮和 1,5-二醇中获得取代的酰基环己烯的原子经济方法。该过程由铱 (I) 催化剂与庞大的富电子膦配体 (CataCXium A) 共同催化,该配体有利于无受体脱氢反应,而不是共轭还原成相应的环己烷。该反应产生水和氢气作为唯一的副产物,并且可以使用该方法以非常高的产率合成范围广泛的官能化酰基环己烯产物。进行了一系列对照实验,结果表明该过程是由二醇的无受体脱氢引发的,然后是氧化还原中性级联过程,该过程与铱催化剂无关。氘标记研究表明,该级联的关键步骤涉及一种新型碱介导的 [1,5]-氢化物转移。环己烯基酮产物在弱酸性条件下很容易裂解,以获得一系列有价值的取代环己烯衍生物。
USE OF NITROGEN COMPOUNDS QUATERNISED WITH ALKYLENE OXIDE AND HYDROCARBYL-SUBSTITUTED POLYCARBOXYLIC ACID AS ADDITIVES IN FUELS AND LUBRICANTS
申请人:BASF SE
公开号:US20160130514A1
公开(公告)日:2016-05-12
The invention relates to the use of quaternized nitrogen compounds as a fuel and lubricant additive or kerosene additive, such as in particular as a detergent additive, for decreasing or preventing deposits in the injection systems of direct-injection diesel engines, in particular in common rail injection systems, for decreasing the fuel consumption of direct-injection diesel engines, in particular of diesel engines having common rail injection systems, and for minimizing the power loss in direct-injection diesel engines, in particular in diesel engines having common rail injection systems; the invention further relates to the use as an additive for petrol, in particular for operation of DISI engines.
Studies on the Conversions of Diols and Cyclic Ethers. Part 48. Dehydration of alcohols and diols on the action of dimethylsulfoxide
作者:Árpád Molnár、Mihály Bartók
DOI:10.1002/hlca.19810640204
日期:1981.3.18
The transformations of 13 alcohols and 13 diols in the presence of a small amount dimethylsulfoxide (1/16 mol) were studied. Relationships were found between the type of the hydroxy compound and the selectivity of the transformation, and conclusions were drawn regarding the transformation mechanism. The ether formation observed with certain alcohols proceeds via a carbenium cation. The reaction conditions
Fe‐Catalyzed Anaerobic Mukaiyama‐Type Hydration of Alkenes using Nitroarenes
作者:Anup Bhunia、Klaus Bergander、Constantin Gabriel Daniliuc、Armido Studer
DOI:10.1002/anie.202015740
日期:2021.4.6
Hydration of alkenes using first row transitionmetals (Fe, Co, Mn) under oxygen atmosphere (Mukaiyama‐type hydration) is highly practical for alkene functionalization in complex synthesis. Different hydration protocols have been developed, however, control of the stereoselectivity remains a challenge. Herein, highly diastereoselective Fe‐catalyzed anaerobic Markovnikov‐selective hydration of alkenes
Asymmetric Hydrosilylation of Ketones Using<b><i>Trans</i></b>-Chelating Chiral Peralkylbisphosphine Ligands Bearing Primary Alkyl Substituents on Phosphorus Atoms
作者:Ryoichi Kuwano、Masaya Sawamura、Junya Shirai、Masatoshi Takahashi、Yoshihiko Ito
DOI:10.1246/bcsj.73.485
日期:2000.2
Asymmetric hydrosilylation of simple ketones with diphenylsilane proceeded at -40 °C in the presence of a rhodium complex (0.001—0.01 molar amount) coordinated with a trans-chelating chiral bisphosphine ligand bearing linear alkyl substituents on the phosphorus atoms, (R,R)-(S,S)-Et-, Pr-, or BuTRAP, giving the corresponding optically active (S)-secondary alcohols with up to 97% ee. The asymmetric
简单酮与二苯基硅烷的不对称氢化硅烷化在 -40 °C 下在铑配合物(0.001-0.01 摩尔量)存在下进行,该配合物与在磷原子上带有线性烷基取代基的反式螯合手性双膦配体(R,R) -(S,S)-Et-、Pr- 或 BuTRAP,得到相应的光学活性 (S)-仲醇,其 ee 高达 97%。使用具有更大 P 取代基的 TRAP 配体的不对称氢化硅烷化导致低得多的对映选择性。EtTRAP-铑催化剂对于具有铑原子配位位点的酮酯的不对称氢化硅烷化也有效(高达 98% ee)。通过使用 2.5 摩尔二苯基硅烷的不对称还原,从相应的二酮中获得了高达 99% ee 的旋光对称二醇。