136408-25-8Relevant academic research and scientific papers
Br?nsted Acid Catalysis in Visible-Light-Induced [2+2] Photocycloaddition Reactions of Enone Dithianes
Brenninger, Christoph,P?thig, Alexander,Bach, Thorsten
supporting information, p. 4337 - 4341 (2017/04/04)
1,3-Dithiane-protected enones (enone dithianes) were found to undergo an intramolecular [2+2] photocycloaddition under visible-light irradiation (λ=405 nm) in the presence of a Br?nsted acid (7.5–10 mol %). Key to the success of the reaction is presumably the formation of colored thionium ions, which are intermediates of the catalytic cycle. Cyclobutanes were thus obtained in very good yields (78–90 %). It is also shown that the dithiane moiety can be reductively or oxidatively removed without affecting the photochemically constructed ring skeleton.
Regiochemistry of the Intramolecular Photocycloaddition of Enones to Vinyl Ethers as a Function of Chain Length
Gleiter, Rolf,Fischer, Evelyn
, p. 1899 - 1912 (2007/10/02)
The intramolecular cycloaddition of a cyclohexenone moiety bound to a vinyl ether fragment has been explored.The regiochemistry and the quantum yield of the reaction has been investigated as a function of the chain length n and the position of the methoxy group.It has been found that in those cases where the chain consists of three and four members the position of the methoxy group has no influence on the regiochemistry but on the quantum yield.Only head-to-head cycloaddition is observed.In the case of n = 2 both the regiochemistry and the quantum yield depend strongly on the position of the methoxy group.It is concluded that the main reason for the different behavior of n = 2 is due to a through-bond effect between the two olefinic units mediated by a C2H4 bridge. Key Words: Rule of five / Photocycloaddition / Regiochemistry / Enones / Vinyl ethers
