The photochemical cyclodimerisation of cycloheptene and cyclooctene has been studied under irradiation at 254 nm, using copper(I) triflate as catalyst. Two cycloheptene dimers cis-anti-cis- and trans-syn-trans-tricyclo [7.5.0.02,8] tetradecane and five cyclooctene dimers (all stereoisomeric tricyclo [8.6.0.02,9] hexadecanes) have been obtained. The 1H and 13C NMR spectra of the cyclooctene dimers show
使用三氟甲磺酸铜(I)作为催化剂,在254 nm的辐射下研究了环庚烯和环辛烯的光化学环二聚反应。已获得两个环庚烯二聚体顺-反-顺-和反-顺-反-三环[7.5.0.0 2,8 ]十四烷和五个环辛烯二聚体(所有立体异构体三环[8.6.0.0 2,9 ]十六烷)。环辛烯二聚体的1 H和13 C NMR光谱显示,由于环丁烷环的褶皱,环丁基氢的高场位移(从2.4到1 ppm)和环丁基碳共振的低场位移。随着环褶皱的增加,它们的GC保留时间减少。
Thermal [2 + 2] cyclodimerisation of strained olefins. Cis, trans-1,5-cyclo-octadiene and trans-cyclo-octene
作者:Johannes Leitich
DOI:10.1016/0040-4020(82)85118-1
日期:1982.1
been investigated both with the racemic and with the optically active cycloolefins. Both title olefins form [2 + 2] dimers of the trans double bonds with complete retention of configuration (trans-syn-trans 2 by R + S and trans-anti-trans 3 by R + R combination) and with mono-inversion (cis,trans 4, both by R + S and R + R combinations), but almost none with di-inversion (cis-syn-cis 5 and cis-anti-cis
Photochemistry of 2,4-Cyclooctadienone I. In Benzene and Toluene
作者:Gordon L. Lange、Eli Neidert
DOI:10.1139/v73-332
日期:1973.7.1
Irradiation of 2,4-cyclooctadienone (1) in benzene or toluene is shown to give in >80% yield two head-to-head dimers. The ring fusions are shown to occur at the α,β-positions of the dienone with trans-cis and trans-anti-trans stereochemistry. Both dimers may be epimerized to the same product with cis-anti-cis ring fusions. Evidence is presented to show that the singlet state is responsible for the