53830-89-0Relevant academic research and scientific papers
Ring-opening of benzocyclobutenol with mild bases and trapping with dieneophiles
Shaw, Simon J.
, p. 4183 - 4189 (2007)
The treatment of benzocyclobutenol with a mild base has been investigated. This reaction results in an electrocyclic opening of the cyclobutene to the corresponding o-quinodimethane, which has been successfully treated with aldehydes and electron-deficient alkenes to form benzolactols and benzocyclohexenes respectively. Copyright Taylor & Francis Group, LLC.
Generation of and diastereoselective cycloaddition reactions to ortho-quinodimethane tricarbonylchromium intermediates
Kuendig, E. Peter,Leresche, James
, p. 5599 - 5615 (1993)
Reaction of n-BuLi with either syn- or anti-(1-acetoxycyclobutabenzene)Cr(CO)3 or with syn-(1-hydroxycyclobutabenzene) generates a planar chiral o-quinodimethane complex intermediate at temperatures below 0°C. This reacts with reactive dienophiles (methyl acrylate, acrylonitrile, phenyl vinyl sulfone, 1-phenyl-2-(phenylsulfonyl)ethene, methyl crotonate, dimethyl fumarate and dimethyl maleate) to give cycloaddition products. X-ray structures of three complexes show that (anti-1-tetrahydronaphthol)Cr(CO)3 complexes are formed selectively. With ester and nitrile substituted olefins, the major diastereoisomer is the cis product (endo-addition) whereas the trans product (exo addition) is largely preferred for vinyl sulfones. The results are compared with those obtained with the free cyclobutabenzenes. After decomplexation, the β-hydroxy ester products can be alkyl- or allylated highly diastereoselectively. First examples of diastereoselective complexation of enantiomerically enriched cyclobutabenzenes are reported.
Mechanistic Studies on the Photogenerated Dienol with α-Phenyl-N-tert-Butylnitrones
Pan, Kai,Ho, Tong-Ing
, p. 243 - 247 (2007/10/03)
The mechanism for the photochemical reactions of o-methyl-benzaldehyde (1), o-methyl-acetophenone (2) and o-methyl-benzophenone (3) in the presence of α-phenyl-N-tert-butylnitrone (PBN) to the formation of stable nitroxyl radicals 4-6 is studied. The nitroxyl radical product 6 can also be obtained by the thermolysis of benzocyclobutenol with PBN. Thus, the radical products were derived from a novel and regioselective 4+2 cycloaddition of the photogenerated dienol intermediate with PBN.
ω-Hydroxy-ortho-quinodimethane: Trapping with Trifluoroacetone and Photocyclization
Griesbeck, Axel G.,Stadtmueller, Stefan
, p. 2149 - 2150 (2007/10/02)
ω-Hydroxy-ortho-quinodimethane (2), generated by photoenolization of 2-methylbenzaldehyde (1) in benzene, is quantitatively trapped with trifluoroacetone to give the bicyclic hemiacetal 6 and the hydroxy aldehyde 7.A less effective trapping reaction is observed with benzaldehyde with the formation of the bicyclic hemiacetal 5.The formation of benzocyclobutenol 4 is probable due to a two-photon process involving electronically excited 2. - Key Words: Photochemistry/ ortho-Chinodimethanes/ Trapping reactions/ Two-photon chemistry
