- Asymmetric organocatalytic vinylogous Michael addition triggered triple-cascade reactions of 2-hydroxycinnamaldehydes and vinylogous nucleophiles: construction of benzofused oxabicyclo[3.3.1]nonane scaffolds
-
An organocatalytic vinylogous Michael addition triggered triple-cascade reaction has been developed. 2-Hydroxycinnamaldehydes worked under iminium activation with either acyclic or cyclic ketone-derived α,α-dicyanoalkenes, yielding the benzofused oxabicyclo[3.3.1]nonanes bearing one quaternary stereocenter with excellent stereoselectivities.
- Wu, Hui-Chun,Wang, Chen,Chen, Ying-Han,Liu, Yan-Kai
-
supporting information
p. 1762 - 1765
(2021/02/27)
-
- Complex Hydroindoles by an Intramolecular Nitrile-Intercepted Allylic Alkylation Cascade Reaction
-
Bisnucleophilic reagents derived from malononitrile, ketones, benzaldehydes, and nitromethane can react with bisallylic electrophiles via a nitrile-intercepted allylic alkylation cascade reaction to yield complex hydroindole architectures. Also noteworthy
- Vertesaljai, Peter,Ghiviriga, Ion,Grenning, Alexander J.
-
supporting information
p. 1970 - 1973
(2018/04/16)
-
- Deconjugative alkylation/Heck reaction as a simple platform for dihydronaphthalene synthesis
-
A simple platform for carbocycle synthesis by Knoevenagel adduct deconjugative alkylation/Heck reaction is described. Deconjugative alkylation of Knoevenagels adducts is two-fold synthetically enabling because C-C bond formation is (1) operationally simple due to the ease of Knoevenagel adduct carbanion generation and (2) results in alkene migration, which poises the substrate for cyclization. Furthermore, the gem-dinitrile moiety serves as a functional group for synthetic manipulation.
- Navaratne, Primali V.,Grenning, Alexander J.
-
supporting information
p. 69 - 75
(2016/12/27)
-
- Transfer hydrogenation of activated C=C bonds catalyzed by ruthenium amido complexes: Reaction scope, limitation, and enantioselectivity
-
(Chemical Equation Presented) It was found that the chemoselectivity could be completely switched from C=O to C=C bonds in the transfer hydrogenation of activated α,β-unsaturated ketones catalyzed by diamine-ruthenium complex. Moreover, this addition via metal hydride had been applied to the reduction of various activated olefins. The electron-withdrawing ability of functional groups substituted on C=C bonds at the α- or β-position had strong influence on the reactivity. In addition, a wide variety of chiral diamine-Ru(II)-(arene) systems was investigated to explore the asymmetric transfer hydrogenation of prochiral α,α-dicyanoolefins. Two parameters had been systematically studied, (i) the structure of the N-sulfonylated chiral diamine ligands, in which several chiral diamines substituted on the benzene ring of DPEN were first reported, and (ii) the structure of the metal precursors, and high enantioselectivitiy (up to 89% ee) at the β-carbon was obtained.
- Xue, Dong,Chen, Ying-Chun,Cui, Xin,Wang, Qi-Wei,Zhu, Jin,Deng, Jin-Gen
-
p. 3584 - 3591
(2007/10/03)
-
- A convenient and selective one-pot method for the synthesis of monosubstituted secondary alkyl malononitriles
-
We have found that α,α-dicyanoalkenes can be efficiently and selectively reduced to α,α-dicyanoalkanes (malononitriles) with NaBH4 in 95% EtOH at 0 °C. In addition, we have determined that the condensation of malononitrile with ketones using absorption alumina as a catalyst can be followed directly, in one pot, by reduction with NaBH 4 in 95% EtOH at 0 °C to provide the monosubstituted secondary alkyl malononitriles in good to excellent yields (42-94%). This procedure provides a convenient alternative to direct alkylation of malononitrile or reduction of α,α-dicyanoalkene intermediates.
- Sammelson, Robert E.,Allen, Mark J.
-
p. 543 - 546
(2007/10/03)
-
- Geminal dinitriles and their reactions: I. Hydrolysis of alkylidene- and cycloalkylidenemalononitriles in aqueous medium
-
The kinetics of pseudounimolecular hydrolysis of alkylidene- and cycloalkylidenemalononitriles in an aqueous buffer at pH 7 were studied. Correlations between the rate constants and substituent effects were found to fit the Taft-Hancock equation. Electrochemical reduction of alkylidenemalononitriles was studied using 0.2 M tetraethylammonium iodide as supporting electrolyte. The half-wave reduction potentials are related to the substituent constants σ* by the Taft-Zuman equation. Anomalous behavior of 1,1-dicyano-2,3,3-trimethyl-1-butene was observed during the hydrolysis and electrochemical reduction at a dropping mercury electrode.
- Smirnov,Sevast'yanova
-
p. 1703 - 1708
(2007/10/03)
-
- The Reaction between Diazoalkanes and Allylic Halides Carrying Electronegative γ-Substituents. 1. Solvent Effects in the Decomposition of 4-(1-Bromo-1-methylethyl)-4,5-dihydro-3H-3,3-pyrazoledicarbonitrile
-
The formation of the title compound and its decomposition in several solvents is described.In nonpolar solvents both a cyclopropane and an olefinic product are formed in polar solvents, both protic and aprotic, the cyclopropane is the only product observed.Rate of formation of the cyclopropane is very solvent dependent, while the olefin is formed at nearly the same rate in all solvents.The presence of the bromine atom in the side chain has a very great effect on the product distribution and on the rate of cyclopropane formation.Bonding in the proposed transition state is discussed.
- Kolsaker, Per,Storesund, Hans-Johan,Gulbrandsen, Trygve,Woien, Grete
-
p. 187 - 196
(2007/10/02)
-