- Nickel-Catalyzed Asymmetric Reductive Arylbenzylation of Unactivated Alkenes
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Herein, we report a nickel-catalyzed asymmetric two-component reductive dicarbofunctionalization of aryl iodide-tethered unactivated alkenes using benzyl chlorides as the challenging coupling partner. This arylbenzylation reaction enables the efficient synthesis of diverse benzene-fused cyclic compounds bearing a quaternary stereocenter with a high tolerance of sensitive functionalities in highly enantioselective manner. The preliminary mechanistic investigations suggest a radical chain reaction mechanism.
- Jin, Youxiang,Yang, Haobo,Wang, Chuan
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supporting information
p. 2724 - 2729
(2020/04/02)
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- Nickel-Catalyzed Reductive Arylalkylation via a Migratory Insertion/Decarboxylative Cross-Coupling Cascade
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Reported is a nickel-catalyzed reductive arylalkylation of unactivated alkenes tethered to aryl iodides with redox active N-hydroxyphthalimide esters as the alkyl source through successful merging of migratory insertion and decarboxylative cross-coupling in a cascade. This new method avoids the use of pregenerated organometallic reagents and thus enables the synthesis of diverse benzene-fused carbo- and heterocyclic compounds with high tolerance of a wide range of functional groups.
- Jin, Youxiang,Yang, Haobo,Wang, Chuan
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supporting information
p. 7602 - 7608
(2019/10/02)
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- Photochemistry of 3-methyl- and 4-methyl-1,2-dihydronaphthalene in the gas phase1
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The photochemistry of 3-methyl-1,2-dihydronaphthalene (3-MDHN) and 4-methyl-1,2-dihydronaphthalene (4-MDHN) has been studied in the gas phase. Photolysis of 3-MDHN with 254-nm light produces 2-methyl-1,2-dihydronaphthalene (2-MDHN) as the major primary product. Naphthalene is also formed, apparently as a secondary photoproduct from 2-MDHN. Addition of butane to the photolysis mixture quenches the formation of 2-MDHN while producing a new photoproduct, 1-isopropenylbenzocyclobutene (IBCB). This product is also formed when light centered at 300 nm is used for the photolysis. Photolysis of 4-MDHN vapor with 254-nm light gives three products unique to the gas phase: 1-isopropenyl-2-vinylbenzene (IVB), 3-(o-tolyl)-1,2-butadiene (T12B), and 1-methyl-1,2-dihydronaphthalene (1-MDHN). An apparent alkyl shift product, 3-methyl-1,2-dihydronaphthalene (3-MDHN), and naphthalene are also formed, apparently as secondary photolysis products from 1-MDHN. In addition, several photoproducts common to both the solution and gas phase are detected: 2-(o-tolyl)-1,3-butadiene (T13B), 1-methylbenzobicyclo[3.1.0]hex-2-ene (1-MBBH), 1-methyl-1,4-dihydronaphthalene (1-M-1,4-DHN), 1-methyltetralin (1-MT), and 1-methylnaphthalene (1-MN). Again, the presence of butane during the 254-nm photolysis, or the use of longer wavelength light, gives rise to a new photoproduct, 1-methyl-1-vinylbenzocyclobutene (MVBCB). The fluorescence excitation spectrum for 4-MDHN confirms that 254-nm excitation into S2 leads to minimal population of the emissive vibrational levels of S1. Two pathways appear to dominate the photochemistry: retro [4 + 2] cycloaddition to give o-quinodimethane intermediates and sequential hydrogen shifts. These pathways derive from S2 and/or upper vibrational levels of S1 (S1vib) as indicated by the characteristic responses of their ultimate products to the presence of buffer gas. The benzocyclobutenes are unique; they are postulated to arise through a 2 + 2 closure of a vibrationally relaxed precursor o-quinodimethane or via a [1,3] sigmatropic shift in a uniquely populated set of S1vib levels.
- Duguid, Robert J.,Morrison, Harry
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p. 1271 - 1281
(2007/10/02)
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- Flash Vacuum Pyrolysis of N-Allyl-Substituted 1,3,4-Oxadiazolin-5-ones
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The flash vacuum pyrolysis of several N-allyl-substituted 1,3,4-oxadiazolin-5-ones generates nitrile imines which rearrange to diazoalkenes via a 3,3-sigmatropic shift.
- Padwa, Albert,Caruso, Thomas,Nahm, Steven
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p. 4065 - 4067
(2007/10/02)
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