Ru-Catalyzed Migratory Geminal Semihydrogenation of Internal Alkynes to Terminal Olefins
作者:Lijuan Song、Qiang Feng、Yong Wang、Shengtao Ding、Yun-Dong Wu、Xinhao Zhang、Lung Wa Chung、Jianwei Sun
DOI:10.1021/jacs.9b09658
日期:2019.10.30
the gem-H2 Ru-carbene might be the key intermediate in both gem- and trans-addition reactions, rather than the Ru-vinylidene intermediate. The DFT results were further supported by carefully designed control experiments. This uncommon gem-addition combined with 1,2-silyl migration in the metal-carbene intermediate should open up a new synthetic avenue for alkyne transformations.
A highly enantioselective and atom-economical [2 + 2] cycloaddition of various alkynes with trifluoropyruvate using a dicationic (S)-BINAP-Pd catalyst has been established. This is the first enantioselective synthesis of stable oxetene derivatives, whose structure has been clarified by X-ray analysis. This catalytic process offers a practical synthetic method for oxetene derivatives (catalyst loading:
catalytic asymmetric ene reaction with difluoropyruvate as an electrophile in the presence of a dicationic palladium complex is shown. This is the reliable and practical catalytic asymmetric synthesis for various α-CF2H tertiary alcohols in high yields and enantioselectivities. The reaction with isobutene can be catalyzed efficiently under solvent-free conditions with lowcatalystloading (up to S/C 2000)
显示了在阳离子型钯络合物存在下,以二氟丙酮酸酯为亲电体的催化不对称烯反应。这是可靠和实用催化不对称合成各种α-CF 2以高产率和对映选择性ħ叔醇。与异丁烯的反应可以在无溶剂条件下以较低的催化剂负载量(高达S / C 2000)有效地进行催化。此外,二氟丙酮酸盐可高产率和对映选择性地用于[2 + 2]环加成反应。
Organophotocatalytic silyl transfer of silylboranes enabled by methanol association: a versatile strategy for C–Si bond construction
including late-stage functionalization and radical cascade reactions. Furthermore, this technology could be extended to the construction of C–B, C–S and C–Sn bonds, thus offering a versatile platform for bond activation and connection of main group elements. The green aspect of the reaction has also been demonstrated by using Brij-30/water as a reaction solvent or sunlight as an alternative energy source
Alkali Metal-Hydroxide-Catalyzed C(<i>sp</i>)–H Bond silylation
作者:Anton A. Toutov、Kerry N. Betz、David P. Schuman、Wen-Bo Liu、Alexey Fedorov、Brian M. Stoltz、Robert H. Grubbs
DOI:10.1021/jacs.6b12114
日期:2017.2.1
Disclosed is a mild, scalable, and chemoselective catalytic cross-dehydrogenative C-H bond functionalization protocol for the construction of C(sp)-Si bonds in a single step. The scope of the alkyne and hydrosilane partners is substantial, providing an entry point into various organosilane building blocks and additionally enabling the discovery of a number of novel synthetic strategies. Remarkably, the optimal catalysts are NaOH and KOH.