16554-83-9Relevant articles and documents
Stereochemistry of the Diels-Alder Reaction of Butadiene with Cyclopropene
Baldwin, John E.,Reddy, V. Prakash
, p. 5264 - 5267 (1989)
1(E)-Deuteriobutadiene and cyclopropene react at 0 deg C to give 2-endo-deuteriobicyclohept-3-ene; 1(Z)-deuteriobutadiene leads to the 2-exo-deuterio bicyclic product.Analysis of these products through 2H NMR spectroscopy reveals complete stereospecificity, indicating that the transition structure having an endo orientation of diene and cyclopropene is strongly favored over the alternative exo geometry.
Cage escape competes with geminate recombination during alkane hydroxylation by the diiron oxygenase AlkB
Austin, Rachel N.,Luddy, Kate,Erickson, Karla,Pender-Cudlip, Marilla,Bertrand, Erin,Deng, Dayi,Buzdygon, Ryan S.,Van Beilen, Jan B.,Groves, John T.
supporting information; experimental part, p. 5232 - 5234 (2009/04/04)
(Chemical Presented) AlkBstops the radical clock: Three structurally analogous radical-clock substrates with a large span in their rearrangement rates are hydroxylated by AlkB to afford similar amounts of rearranged (2) and unrearranged products (1). Such a result is in accord with radical rebound competing with cage escape of the geminate substrate radical. The results show that radical clocks can measure both the radical lifetime and the kinetics of cage escape.
Products from enzyme-catalyzed oxidations of norcarenes
Newcomb, Martin,Lansakara-P, Dharmika S. P.,Kim, Hye-Yeong,Chandrasena, R. Esala P.,Lippard, Stephen J.,Beauvais, Laurance G.,Murray, Leslie J.,Izzo, Viviana,Hollenberg, Paul F.,Coon, Minor J.
, p. 1128 - 1133 (2007/10/03)
(Chemical Equation Presented) Recent studies revealed that norcarane (bicyclo[4.1.0]heptane) is oxidized to 2-norcarene (bicyclo[4.1.0]-hept-2-ene) and 3-norcarene (bicyclo[4.1.0]hept-3-ene) by iron-containing enzymes and that secondary oxidation products from the norcarenes complicate mechanistic probe studies employing norcarane as the substrate (Newcomb, M.; Chandrasena, R. E. P.; Lansakara-P., D. S. P.; Kim, H.-Y.; Lippard, S. J.; Beauvais, L. G.; Murray, L. J.; Izzo, V.; Hollenberg, P. F.; Coon, M. J. J. Org. Chem. 2007, 72, 1121-1127). In the present work, the product profiles from the oxidations of 2-norcarene and 3-norcarene by several enzymes were determined. Most of the products were identified by GC and GC-mass spectral comparison to authentic samples produced independently; in some cases, stereochemical assignments were made or confirmed by 2D NMR analysis of the products. The enzymes studied in this work were four cytochrome P450 enzymes, CYP2B1, CYPΔ2E1, CYPΔ2E1 T303A, and CYPΔ2B4, and three diiron-containing enzymes, soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath), toluene monooxygenase (ToMO) from Pseudomonas stutzeri OX1, and phenol hydroxylase (PH) from Pseudomonas stutzeri OX1. The oxidation products from the norcarenes identified in this work are 2-norcaranone, 3-norcaranone, syn- and anti-2-norcarene oxide, syn- and anti-3-norcarene oxide, syn-and anti-4-hydroxy-2-norcarene, syn- and anti-2-hydroxy-3-norcarene, 2-oxo-3-norcarene, 4-oxo-2-norcarene, and cyclohepta-3,5-dienol. Two additional, unidentified oxidation products were observed in low yields in the oxidations. In matched oxidations, 3-norcarene was a better substrate than 2-norcarene in terms of turnover by factors of 1.5-15 for the enzymes studied here. The oxidation products found in enzyme-catalyzed oxidations of the norcarenes are useful for understanding the complex product mixtures obtained in norcarane oxidations.
Desaturase reactions complicate the use of norcarane as a mechanistic probe. Unraveling the mixture of twenty-plus products formed in enzyme-catalyzed oxidations of norcarane
Newcomb, Martin,Chandrasena, R. Esala P.,Lansakara-P, Dharmika S. P.,Kim, Hye-Yeong,Lippard, Stephen J.,Beauvais, Laurance G.,Murray, Leslie J.,Izzo, Viviana,Hollenberg, Paul F.,Coon, Minor J.
, p. 1121 - 1127 (2007/10/03)
(Chemical Equation Presented) Norcarane, bicyclo[4.1.0]heptane, has been widely used as a mechanistic probe in studies of oxidations catalyzed by several iron-containing enzymes. We report here that, in addition to oxygenated products, norcarane is also oxidized by iron-containing enzymes in desaturase reactions that give 2-norcarene and 3-norcarene. Furthermore, secondary products from further oxidation reactions of the norcarenes are produced in yields that are comparable to those of the minor products from oxidation of the norcarane. We studied oxidations catalyzed by a representative spectrum of iron-containing enzymes including four cytochrome P450 enzymes, CYP2B1, CYPΔ2B4, CYPΔ2E1, and CYPΔ2E1 T303A, and three diiron enzymes, soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath), toluene monooxygenase (ToMO) from Pseudomonas stutzeri OX1, and phenol hydroxylase (PH) from Pseudomonas stutzeri OX1. 2-Norcarene and 3-norcarene and their oxidation products were found in all reaction mixtures, accounting for up to half of the oxidation products in some cases. In total, more than 20 oxidation products were identified from the enzyme-catalyzed reactions of norcarane. The putative radical-derived product from the oxidation of norcarane, 3- hydroxymethylcyclohexene (21), and the putative cation-derived product from the oxidation of norcarane, cyclohept-3-enol (22), coelute with other oxidation products on low-polarity GC columns. The yields of product 21 found in this study are smaller than those previously reported for the same or similar enzymes in studies where the products from norcarene oxidations were ignored, and therefore, the limiting values for lifetimes of radical intermediates produced in the enzyme-catalyzed oxidation reactions are shorter than those previously reported.
PHOTOLYSIS OF THE AZOALKANE 2,3-DIAZATRICYCLO4,9>NON-2-ENE: DIRECT OBSERVATION OF 4-CYCLOHEXENYLDIAZOMETHANE
Adam, Waldemar,Carballeira, Nestor,Gillaspey, William D.
, p. 5473 - 5476 (2007/10/02)
Besides denitrogenation to the tricycloalkane 8, the photolysis of azoalkane 3 affords the diazoalkane 4, which serves as precursor to the minor hydrocarbon products 9, 10 and 11; irradiation of azoalkane 3 with the 333.6 nm line of an 18-W argon ion laser was essential to obtain preparative quantities of diazoalkane 4 for its detection and identification.
