Recueil des Travaux Chimiques des Pays-Bas p. 549 - 562 (1988)
Update date:2022-08-03
Topics:
Koppes, Margareth J. C. M.
Cerfontain, Hans
The photochemistry of the α-phenyl-β,γ-enones 3-6 has been studied under conditions of direct (λ 300 nm) and triplet-sensitized irradiation.Upon direct irradiation, 3 exhibits decarbonylation, a 1,3-acyl shift (1,3-AS) and an oxa-di-?-methane (ODPM) rearrangement.Under the same conditions, 4, on the other hand, affords only the ODPM product whereas 5 gives the decarboxylation, 1,3-AS and ODPM products.The formation of the ODPM product of 5 is efficiently quenched by triplet quenchers in contrast to the ODPM products of 3 and 4, the quantum yields of which are not reduced upon the addition of typical triplet quenchers.Triplet-sensitized irradiation of 5 leads to the ODPM rearrangement, whereas surprisingly 3 and 4 are unreactive.It is suggested that the ODPM rearrangement, upon direct irradiation of 3 and 4, proceeds from the S2(??*) state.The ODPM product formed upon direct irradiation of 5 is thought to be formed from the T1(??*) state populated by ISC from the S1(n?*) state.Upon direct irradiation, 6 exhibits a reversible 1,3-AS and in addition ketene formation via an intramolecular 1,5-H shift.Under conditions of triplet photosensitization, compound 6 appears to be stable.Given the apparently different photochemical behaviour of these constrained compounds, a general reactivity pattern for the direct and sensitized irradiation cannot be defined.
View Morejiangsu senxuan pharmaceutical and chemical co.,ltd
Contact:86-523-87982810
Address:hongqiao industrial zone,taixing,jiangsu china
Springchem New Material Technology Co.,Limited
website:http://www.spring-chem.com
Contact:86-21-62885108
Address:602B, Building 1, No. 641, Tianshan Road
Contact:+86-518-81061113
Address:No. 8 Lingzhou Road, Lianyungang, Jiangsu, China
Shandong Jusage Technology Co.,Ltd.
Contact:86-13406130167
Address:No.20,North Ride No.9 Road, Guangrao Economic Development Zone, Shandong Province
Hubei Lansun Biochemical Pharmaceutical Co., Ltd
Contact:714-6395977
Address:No. 81 Pengcheng Avenue, economic and technological development zone, Huangshi City, Hubei Province,China
Doi:10.1016/0008-6215(88)84041-2
(1988)Doi:10.1016/S0040-4039(00)82125-5
(1988)Doi:10.1016/0008-6215(88)84002-3
(1988)Doi:10.1016/0031-9422(90)89043-9
(1990)Doi:10.1016/S0040-4039(00)80801-1
(1988)Doi:10.1039/c8cc06358c
(2018)