共查询到20条相似文献,搜索用时 15 毫秒
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(36):11007-11011
Regio‐ and enantioselective [4+2] annulation between β,γ‐unsaturated α‐keto esters and non‐activated allenes was achieved by using a chiral cationic indium(III)/phosphate catalyst. The reaction affords the corresponding C3‐selective dihydropyrans in good yields and with high enantioselectivity (up to 99 % ee ). 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(11):2973-2977
The first catalytic formal [5+4] cycloaddition to prepare nine‐membered heterocycles is presented. Under palladium catalysis, the reaction of N‐tosyl azadienes and substituted vinylethylene carbonates (VECs) proceeds smoothly to produce benzofuran‐fused heterocycles in uniformly high efficiency. Highly diastereoselective functionalization of the nine‐membered heterocycles through peripheral attack is also demonstrated. 相似文献
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Eric D. Bloch Wendy L. Queen Matthew R. Hudson Jarad A. Mason Dianne J. Xiao Leslie J. Murray Roxana Flacau Craig M. Brown Jeffrey R. Long 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(30):8747-8751
A chromium(II)‐based metal–organic framework Cr3[(Cr4Cl)3(BTT)8]2 (Cr‐BTT; BTT3−=1,3,5‐benzenetristetrazolate), featuring coordinatively unsaturated, redox‐active Cr2+ cation sites, was synthesized and investigated for potential applications in H2 storage and O2 production. Low‐pressure H2 adsorption and neutron powder diffraction experiments reveal moderately strong Cr–H2 interactions, in line with results from previously reported M‐BTT frameworks. Notably, gas adsorption measurements also reveal excellent O2/N2 selectivity with substantial O2 reversibility at room temperature, based on selective electron transfer to form CrIII superoxide moieties. Infrared spectroscopy and powder neutron diffraction experiments were used to confirm this mechanism of selective O2 binding. 相似文献
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Long Li Bo Zhou Yong‐Heng Wang Chao Shu Yi‐Fei Pan Xin Lu Long‐Wu Ye 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(28):8363-8367
An efficient zinc(II)‐catalyzed alkyne oxidation/C H functionalization sequence was developed, thus leading to highly site‐selective synthesis of a variety of isoquinolones and β‐carbolines. Importantly, in contrast to the well‐established gold‐catalyzed intermolecular alkyne oxidation, over‐oxidation can be completely suppressed in this system and the reaction most likely proceeds by a Friedel–Crafts‐type pathway. Mechanistic studies and theoretical calculations are described. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(16):4601-4605
A three‐component palladium‐catalyzed aminocarbonylation of aryl and heteroaryl sp2 C−H bonds using nitroarenes as the nitrogen source was achieved using Mo(CO)6 as the reductant and origin of the CO. This intermolecular C−H bond functionalization does not requires any exogenous ligand to be added, and our mechanism experiments indicate that the palladacycle catalyst serves two roles in the aminocarbonylation reaction: reduce the nitroarene to a nitrosoarene and activate the sp2 C−H bond. 相似文献
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Silvia García‐Rubín Carlos Gonzlez‐Rodríguez Cristina García‐Yebra Jesús A. Varela Miguel A. Esteruelas Carlos Sa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(7):1872-1875
A new synthetic route to dihydrobiphenylenes has been developed. The process involves a mild RuII‐catalyzed [2+2+2] dimerization of ortho‐alkenylarylacetylenes or its more versatile variant, the Ru‐catalyzed [2+2+2] cycloaddition of ortho‐ethynylstyrenes with alkynes. Mechanistic aspects of this [2+2+2] cycloaddition are discussed. 相似文献
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《化学:亚洲杂志》2017,12(1):168-173
A catalytic [2+2+2] cyclotrimerization of unactivated internal alkynes providing cyclotrimerization products in excellent yields with high regioselectivity is described. The transformation is accomplished by using a simple catalytic mixture comprising Ni(acac)2, an imidazolium salt and a Grignard reagent at room temperature or 60 °C for 20 min or 1 h. 相似文献