Cycloreversion of 1-(1-Naphthyl)-5-phenylbicyclo[3.2.0]hept-6-ene to 1-(1-Naphthyl)-4-phenyl-1,3-cycloheptadiene by Triplet Sensitization and Direct Irradiation
been investigated. The triplet sensitization of 1b in benzene gave 2b quantitatively up to a stationary state where the quantum yield was 0.96. The tripletstate of 2b (λmax = 455 nm, τ = 4.6 μs) was formed by the pulseradiolysis of 1b in benzene. It has been found that cycloreversion proceeds by an adiabatic mechanism via a tripletstate. The quantum yield for the formation of 2b by the irradiation
precatalyst and tBuNH2 as the cocatalyst. This catalyst system provides an efficient and atom-economical access to unsymmetrical (E,E)-1,4-diarylbutadienes with high yields and stereoselectivities. Monitoring the process revealed that a sequence of cis-semihydrogenation of the triple bond of 1,3-enynes (to form (E,Z)-butadienes) and (E,Z)-to-(E,E) isomerization occurs to form (E,E)-butadienes.
使用新的 (PCN)Ir 配合物作为预催化剂和t BuNH 2作为助催化剂,开发了以乙醇为氢源的 1,3-烯炔的反式半氢化反应。该催化剂体系以高产率和立体选择性提供了一种高效且原子经济地获得不对称 ( E , E )-1,4-二芳基丁二烯的途径。监测过程显示,1,3-烯炔的三键顺式半氢化(形成 ( E , Z )-丁二烯)和 ( E , Z ) 到-( E , E ) 异构化形成( , _E )-丁二烯。
Base-promoted direct <i>E</i>-selective olefination of organoammonium salts with sulfones toward stilbenes and conjugated 1,3-dienes
deaminative olefination of organoammonium salts was developed. Only mediated by KOtBu, a series of benzyl and cinnamyl ammonium salts reacted smoothly with sulfones, producing the valuable stilbenes and related 1,3-diene derivatives in good to high yields with good functional group tolerance and excellent E-selectivity. With this developed method, biologically active resveratrol and DMU-212 were also successfully
开发了一种碱促进的有机铵盐直接脱氨基烯化。仅由 KO t Bu 介导,一系列苄基和肉桂基铵盐与砜类顺利反应,以良好至高收率生产有价值的二苯乙烯和相关的 1,3-二烯衍生物,具有良好的官能团耐受性和优异的E选择性。利用该方法,还成功制备了具有生物活性的白藜芦醇和DMU-212,进一步证明了该反应的实用性。
LONGO, M. L.;PARISI, G.;PERRINI, G., BOLL. ACCAD. GIOENIA SCI. NATUR., 1982, 15, N 319, 65-73
作者:LONGO, M. L.、PARISI, G.、PERRINI, G.
DOI:——
日期:——
Friedmann; van Heyningen, Journal fuer Praktische Chemie (Leipzig), 1936, vol. <2> 146, p. 163,165