Reversible Cleavage/Formation of the Chromium-Chromium Quintuple Bond in the Highly Regioselective Alkyne Cyclotrimerization
作者:Yu-Siang Huang、Gou-Tao Huang、Yao-Lun Liu、Jen-Shiang K. Yu、Yi-Chou Tsai
DOI:10.1002/anie.201709583
日期:2017.11.27
Herein we report the employment of the quintuply bonded dichromium amidinates [Crκ2‐HC(N‐2,6‐iPr2C6H3)(N‐2,6‐R2C6H3)}]2 (R=iPr (1), Me (7)) as catalysts to mediate the [2+2+2] cyclotrimerization of terminal alkynes giving 1,3,5‐trisubstituted benzenes. During the catalysis, the ultrashort Cr−Cr quintuple bond underwent reversible cleavage/formation, corroborated by the characterization of two inverted
本文我们报告的quintuply结合二铬脒[CR κ就业2 -HC(N-2,6-我镨2 ç 6 ħ 3)(N-2,6-R 2 ç 6 ħ 3)}] 2(R = iPr(1),Me(7))作为催化剂来介导末端炔烃的[2 + 2 + 2]环三聚,得到1,3,5-三取代苯。在催化,超短铬铬五重键经历可逆裂解/形成,由两个反相芳烃夹心络合物二铬(μ-η的表征证实了6:η 6 -1,3,5-(ME 3 Si)的3Ç 6 ħ 3)[CR κ 2 -HC(Ñ -2,6-我镨2 ç 6 ħ 3)(Ñ -2,6-R 2 ç 6 ħ 3)}] 2(R =我PR(5),我(8))。在σ供体,如THF和2,4,6-我的存在3 Ç 6 ħ 2 CN,桥接芳烃1,3,5-(ME 3 Si)的3 Ç 6 ħ 3在5和8被挤出和1和7被再生。理论计算被用来揭示末端炔烃的这些高度区域选择性的[2 + 2 + 2]烷基共三聚反应的反应途径。