4313-57-9Relevant articles and documents
Rhodium(I)-Catalyzed Enantioselective C(sp3)—H Functionalization via Carbene-Induced Asymmetric Intermolecular C—H Insertion?
Liu, Bo,Xu, Ming-Hua
supporting information, p. 1911 - 1915 (2021/05/31)
Transition-metal-catalyzed C—H insertion of metal-carbene represents an excellent and powerful approach for C—H functionalization. However, despite remarkable advances in metal-carbene chemistry, transition metal catalysts that are capable of enantioselective intermolecular carbene C—H insertion are mainly constrained to dirhodium(II) and iridium(III)-based complexes. Herein, we disclose a new version of asymmetric carbene C—H insertion reaction with rhodium(I) catalyst. A highly enantioselective rhodium(I) complex-catalyzed C(sp3)—H functionalization of 1,4-cyclohexadienes with α-aryl-α-diazoacetates was successfully developed. By using chiral bicyclo[2.2.2]-octadiene as ligand, rhodium(I)-carbene-induced asymmetric intermolecular C—H insertion proceeds smoothly at room temperature, allowing access to a diverse variety of α-aryl-α-cyclohexadienyl acetates and gem-diaryl-containing acetates in good yields with good to excellent enantioselectivities (up to 99% ee). Furthermore, the synthetic utility of the reaction was highlighted by facile synthesis of a novel cannabinoid CB1 receptor ligand. This method may offer a new opportunity for the development of therapeutically exploitable cannabinoid receptor type ligands in medicinal chemistry.
Substituent effects on the dehydration of arene hydrates in aqueous solution
O'Mahony, Michelle J.,More O'Ferrall, Rory A.,Boyd, Derek R.,Lam, Casey M.,O'Donoghue, Annmarie C.
supporting information, p. 989 - 996 (2014/01/06)
Rate constants have been determined by UV spectrophotometry at 25 °C for the acid-catalyzed dehydration of different types of monocyclic arene hydrates including those substituted at the 1-, 2- or 3-positions. General acid catalysis was not observed, and linear plots of pseudo-first-order rate constants for dehydration against hydronium concentration were obtained. A Hammett plot of the second-order rate constants for acid-catalyzed dehydration, kH (M-1s-1), of unsubstituted- (8a), 3-substituted (8b, 8c, 8d, 8e) and 1-substituted-benzene hydrates (14f and 14h) shows an excellent correlation with σ+ values and yields a large negative ρ-value of -6.5. The results are consistent with rate-determining formation of a benzenium ion in which direct mesomeric interaction with the substituent occurs, presumably permitted by the coplanar arrangement of the diene and carbocation centre in the intermediate. Data points for 2-substituted arene hydrates (13f, 13g, 13h, 13i) deviate negatively from the Hammett plot as direct mesomeric interaction with the substituent is not possible in the corresponding benzenium intermediates. Copyright 2013 John Wiley & Sons, Ltd. A large negative ρ-value of -6.5 is obtained in a correlation of rate constants for the acid-catalyzed dehydration of arene hydrates with σ+ values. Copyright
3-Methylenetricyclo[3.1.0.02,6]hexane, a tricyclic isomer of toluene: Synthesis and addition onto tetracyanoethylene
Hasselmann, Dieter,Loosen, Klaus,Fischer, Thomas,Kunz, Ulrike,Christl, Manfred
, p. 1374 - 1379 (2007/10/03)
A multistep ring-contraction route starting from tricyclo[4.1.0.02,7]heptan-3-one (1) resulted in a mixture of the title compound 7 and the homofulvene 8 in a ratio of 1:2.5. In a second synthesis, a 3.5:1 mixture of 7 and three additional hydrocarbons was obtained from 4-(phenylsulfanyl)tricyclo [3.1.0.02,6]hexan-3-one (9) in a two-step sequence. On being heated at 175 °C in solution, 7 rearranged to toluene. Treatment of 7 with tetracyanoethylene gave rise to a 1:5 mixture of the [2+2] cycloadduct 16 and the cyclopropadicyclopentene derivative 17. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
