具有三足硅烷醇配体的亚烷基钼属于迄今为止已知的最具活性和选择性的炔复分解催化剂。本文描述了新一代产品,其特点是前所未有的稳定性和实用性,同时又不牺牲前代产品的化学优点。具体来说, 16型吡啶加合物很容易以克级制备,可以在空气中常规称重和处理,并且在手套箱外可以保持完好数月。然而,当溶解在甲苯中时,稳定吡啶配体的自发解离释放出具有优异性能和官能团耐受性的活性物质。具体来说,许多极性和非极性基团、各种质子位点和许多基本官能团被证明是兼容的。通过晶体学和光谱手段(包括95 Mo NMR)对催化剂进行了表征;它们的活性和稳定性进行了详细的基准测试,并且通过天然产物合成的高级应用来说明其有利特性。由于良好的整体应用特性和易于处理,该新系列的配合物预计将取代早期的催化剂,并有助于鼓励更频繁地使用炔复分解反应。
An efficient Pd-catalyzed copper and amine free coupling reaction of acetylene and aryl bromides was achieved with calcium carbide as an acetylene source, using inorganic base and easily prepared, air-stable aminophosphine ligand in common organic solvents, providing symmetric diaryl ethynes in one-pot with yields ranged from moderate to excellent.
作者:Nandini Sharma、Vijay Bahadur、Upendra K. Sharma、Debasmita Saha、Zhenghua Li、Yogesh Kumar、Jona Colaers、Brajendra K Singh、Erik V. Van der Eycken
DOI:10.1002/adsc.201800458
日期:2018.8.17
A microwave‐assisted highly efficient intermolecular C−H functionalization sequence has been developed to access substituted isoquinolones using α‐amino acid esters as a directing group. This methodology enables a wide range of N‐benzoyl α‐amino ester derivatives to react via a Ru‐catalysed C−H bond activation sequence, to form isoquinolones with moderate to excellent yields. As an additional advantage
2-trimethylsilylphenylboronic acid with internal alkynes is developed for the synthesis of 2,3-disubstituted benzosilole derivatives. A range of functional groups, encompassing ketones, esters, amines, aryl bromides, and heteroarenes, are compatible, which provides rapid access to diverse benzosiloles. Sequential 2-fold coupling enablesmodularsynthesis of asymmetrically substituted 1,5-dihydro-1,5-disila-s-indacene
Preparation and Reactions of Mono- and Bis-Pivaloyloxyzinc Acetylides
作者:Carl Phillip Tüllmann、Yi-Hung Chen、Robin J. Schuster、Paul Knochel
DOI:10.1021/acs.orglett.8b01892
日期:2018.8.3
Mono-pivaloyloxyzinc acetylide and bis-pivaloyloxyzinc acetylide were selectively prepared from ethynylmagnesium bromide in quantitative yields. These zinc reagents readily underwent Negishi cross-couplings with (hetero)aryl iodides or bromides as well as subsequent Sonogashira cross-couplings. 1,3-Dipolar cycloadditions of these zinc acetylides with benzylic azides produced zincated and bis-zincated
Cu2O/PPh3/TBAB (n-Bu4NBr) system for the cross-couplingreactions of aryl and heteroarylhalides with terminal alkynes has been developed. Four types of Cu2O, including bulky Cu2O, cubic Cu2O nanoparticles, octahedral Cu2O nanoparticles, and spherical Cu2O nanoparticles, were examined, and the octahedral Cu2O nanoparticles were found to be the most effective catalyst for the reaction. In the presence of the octahedral