Reactions of coordinated cyclic polyolefins. Regio- and stereo-specific cycloadditions of ketenes and tricarbonyl(η4-polyene)iron complexes. Structural evidence for a concerted 2 + 2 mechanism
作者:Zeev Goldschmidt、Shlomo Antebi、Drora Cohen、Israel Goldberg
DOI:10.1016/0022-328x(84)80549-5
日期:1984.10
(II) at room temperature gave regiospecifically the cyclobutanones IV, in which the carbonyl is bonded to the uncoordinated terminal of the conjugated triene. Tricarbonyl(η4-cyclooctatetraene)iron, VI, similarly reacts with dipenylketene to give the regioisomeric cyclobutanone VIII. Single crystal X-ray analysis of tricarbonyl[(η-2,3,4,5)-9-methyl-9-phenylbicyclo[5.2.0]nonan-2,4-dien-8-one]iron (IVa)
烯酮的环加成- [R 1 - [R 2 CCO(R 1 =我,R 2 =苯基; R 1 = R 2 =苯基; R 1 =苯基,R 2 = p -甲苯基)(III)和三羰基( η 4在室温下-cycloheptatriene)铁(II)区域专一性,得到cyclobutanones IV,其中,所述羰基被键合到共轭三烯的不协调终端。三羰基(η 4-环辛酸酯)铁,VI,与二烯基乙烯酮反应,得到区域异构的环丁酮VIII。证实三羰基[(η-2,3,4,5)-9-甲基-9-苯基双环[5.2.0]壬南-2,4-dien-8-一]铁(IVa)的单晶X射线分析在末端位置存在苯基,这为2 s + 2 a协同加成机理提供了立体化学证据。加合物IV经过酸催化的环丁酮环裂解,得到异构体酮VII。二芳基加合物(IVb和IVc)热重排为σ,π-烯丙基配合物IX,也可以通过加热环庚三烯配合物II和二芳基烯酮直接获得。