Photochemistry of Structural Analogues of Previtamin D3: Generality of the Wavelength-Dependent Triene Photocyclization
摘要:
Two structural previtamin Da analogues (R = H, CH3) cyclized photochemically with a 1.4-1.8-fold increase in quantum yields over a 3-nm change in excitation wavelength. The sudden increase in quantum yields is due to the participation and mixing of both 2A and 1B excited states. At lambda less than or equal to 306 nm, the 1B state is initially excited and then (a) partitions between isomerization to the corresponding trans triene isomers, (b) decays to the 2A state to give the corresponding cyclohexadienes, and (c) decays to the ground state. At lambda greater than or equal to 309 nm, the 2A state is directly excited to give the corresponding cyclohexadienes and the relaxation path from 1B state to the ground state or isomerization in the 1B state is diminished.
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作者:Baudin, J. B.、Hareau, G.、Julia, S. A.、Lorne, R.、Ruel, O.
DOI:——
日期:——
Inhoffen; Quinkert, Chemische Berichte, 1954, vol. 87, p. 1418,1422
作者:Inhoffen、Quinkert
DOI:——
日期:——
The Chemistry of 1,3,5-Hexatriene
作者:G. F. Woods、N. C. Bolgiano、D. E. Duggan
DOI:10.1021/ja01612a023
日期:1955.4
An Efficient Julia Olefination Mediated by Magnesium in Ethanol
作者:G Lee
DOI:10.1016/00404-0399(50)1073q-
日期:1995.7.31
Scope and stereochemistry of an olefin synthesis from β-hydroxysulphones
作者:Philip J. Kocienski、Basil Lythgoe、Steven Ruston
DOI:10.1039/p19780000829
日期:——
The synthesis of olefinsfrom β-acyloxy-sulphones by reduction with sodium amalgam in methanol–ethyl acetate can be applied to the preparation of a wide variety of conjugated dienes. When used for the synthesis of 1,2-disubstituted olefins in which the new double bond is either isolated or conjugated, the reaction is highly stereoselective, and leads to the trans-isomers.