Facile, regioselective [4 + 2] cycloaddition involving 1-aryl-4-phenyl-1-azadienes and allenic esters: an efficient route to novel substituted 1-aryl-4-phenyl-1,4-dihydropyridines.

[reaction: see text]1-Aryl-4-phenyl-1-azadienes undergo facile, regioselective [4 + 2] cycloaddition to the C2,C3 pi-bond of allenic esters in refluxing benzene, and the formed adducts undergo a 1,3-H shift to afford novel 2-alkyl-1-aryl-3-ethoxycarbonyl-4-phenyl-1,4-dihydropyridines (78-97%). However, when the reaction is carried at room temperature, besides the [4 + 2] addition, the [2 + 2] mode of addition involving C=N of azadiene and C3,C4 pi-bond of allenic esters also intervenes. The resulting N-aryl-2-ethoxy-carbonyl-methylidene-4-styrylazetidines (17-28%) undergo reorganization on silica gel to afford 2-cyclohexen-1-ones.

[1]  M. Behforouz,et al.  Diels–Alder Reactions of 1-Azadienes , 2000 .

[2]  J. Breitenbucher,et al.  Solid-phase synthesis of 4-aryl-1,4-dihydropyridines via the Hantzsch three component condensation , 2000 .

[3]  E. Corey,et al.  A Convenient and Versatile Route to Hydroquinolines by Inter- and Intramolecular Aza-Diels-Alder Pathways. , 1999, Angewandte Chemie.

[4]  S. Terashima,et al.  Ketene Recognizes 1,3-Dienes in Their s-Cis Forms through [4 + 2] (Diels−Alder) and [2 + 2] (Staudinger) Reactions. An Innovation of Ketene Chemistry , 1999 .

[5]  N. Nishimura,et al.  STEREOSELECTIVE FORMATION OF FORMAL EXO DIELS-ALDER ADDUCTS OF SILYLOXYDIENES AND ALLENECARBOXYLATES , 1999 .

[6]  A. Arrieta,et al.  Competitive Mechanisms and Origins of Stereocontrol in the [2 + 2] Thermal Cycloaddition between Imines and Keteniminium Cations. A Complementary Entry to 2-Azetidinones (beta-Lactams) and Related Compounds. , 1999, The Journal of organic chemistry.

[7]  M. Kimura,et al.  Efficient Entry to Tetrahydropyridines: Addition of Enol Ethers to Allenesulfonamides Involving a Novel 1,3‐Sulfonyl Shift , 1999 .

[8]  D. Cárdenas,et al.  New synthesis of pyridoacridines based on an intramolecular aza-Diels–Alder reaction followed by an unprecedented rearrangement† , 1999 .

[9]  D. Boger,et al.  Regioselective Inverse Electron Demand Diels-Alder Reactions of N-Acyl 6-Amino-3-(methylthio)-1,2,4,5-tetrazines. , 1998, The Journal of organic chemistry.

[10]  Fabio C. Gozzo,et al.  The Simplest Azabutadienes in Their N-Protonated Forms. Generation, Stability, and Cycloaddition Reactivity in the Gas Phase , 1998 .

[11]  P. Chaquin,et al.  INVERSE ELECTRON DEMAND DIELS-ALDER REACTIONS : CYCLOADDITION OF ENOL ETHERS AND ENAMINES WITH 4-SUBSTITUTED 6-NITROBENZOFUROXANS AND A NITROETHYLENE MODEL. AN AB INITIO AND SEMIEMPIRICAL THEORETICAL STUDY , 1997 .

[12]  M. Kimura,et al.  Pronounced Chemo-, Regio-, and Stereoselective [2 + 2] Cycloaddition Reaction of Allenes toward Alkenes and Alkynes , 1997 .

[13]  M. Kimura,et al.  Efficient synthesis of 4-ethenylidene-2-oxazolidinones via palladium-catalyzed aminocyclization of 2-butyn-1,4-diol biscarbamates , 1997 .

[14]  W. Fabian,et al.  PERI-, SITE-, AND REGIOSELECTIVITY IN HETEROCUMULENE-HETERODIENE CYCLOADDITION REACTIONS : AN AB INITIO STUDY OF THE SYSTEM KETENIMINE + ACROLEIN , 1997 .

[15]  Nicholas J. Sisti,et al.  Reactivity of N-Phenyl-1-Aza-2-Cyano-1,3-Butadienes in the Diels-Alder Reaction. , 1996, The Journal of organic chemistry.

[16]  X. López,et al.  Solvent and Substituent Effects in the Periselectivity of the Staudinger Reaction between Ketenes and α,β-Unsaturated Imines. A Theoretical and Experimental Study , 1996 .

[17]  M. Charton,et al.  Substituent Effects on an Inverse Electron Demand Hetero Diels−Alder Reaction in Aqueous Solution and Organic Solvents: Cycloaddition of Substituted Styrenes to Di(2-pyridyl)-1,2,4,5-tetrazine , 1996 .

[18]  M. Johannsen,et al.  A highly chemo- and enantio-selective hetero-Diels–Alder reaction catalysed by chiral aluminium complexes , 1996 .

[19]  J. V. Eynde,et al.  Old reagents, new results: Aromatization of Hantzsch 1,4-dihydropyridines with manganese dioxide and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone , 1995 .

[20]  J. M. Mellor,et al.  Reaction of electron rich alkenes with anilines and formaldehyde: Syntheses of tetrahydroquinolines , 1995 .

[21]  B. Jursic,et al.  Theoretical Study of the BH3-Catalyzed Hetero Diels-Alder Reaction between Ethylene and Nitrosoethylene , 1995 .

[22]  A. Arrieta,et al.  Theoretical and experimental studies on the periselectivity of the cycloaddition reaction between activated ketenes and conjugated imines , 1994 .

[23]  J. Barluenga,et al.  Synthesis of heterocycles from Azadienes , 1994 .

[24]  T. Sordo,et al.  Torquoelectronic effect in the control of the stereoselectivity of ketene-imine cycloaddition reactions , 1993 .

[25]  K. Houk,et al.  Hetero-Diels-Alder reaction transition structures: reactivity, stereoselectivity, catalysis, solvent effects, and the exo-lone-pair effect , 1993 .

[26]  S. Kuduk,et al.  Diels-Alder reaction of 2-cyano-1-azadienes. The effect of nitrogen substituents , 1993 .

[27]  X. López,et al.  A semiempirical theoretical study on the formation of .beta.-lactams from ketenes and imines , 1993 .

[28]  T. Sordo,et al.  An ab initio study on the mechanism of the ketene-imine cycloaddition reaction , 1992 .

[29]  J. Flament,et al.  The STO-3G and 3-21G transition structure of the diels-alder reaction of 1-aza-1,3-butadiene with ethylene , 1992 .

[30]  J. Montgomery,et al.  A contribution to the confusion surrounding the reaction of ketenes with imines to produce β-lactams. A comparison of stereoselectivity dependence on the method of ketene generation : acid chloride/triethylamine vs photolysis of chromium-carbene complexes , 1991 .

[31]  D. Boger,et al.  Inverse electron-demand Diels-Alder reactions of N-sulfonyl .alpha.,.beta.-unsaturated imines: a general approach to implementation of the 4.pi. participation of 1-aza-1,3-butadienes in Diels-Alder reactions , 1991 .

[32]  D. Boger,et al.  Diels-Alder reactions of N-sulfonyl-1-aza-1,3-butadienes : development of a synthetic approach to the streptonigrone C ring , 1991 .

[33]  J. Bourguignon,et al.  Broadening in the scope of NADH models by using chiral and non chiral pyrrolo [2,3-bl pyridine derivatives. , 1991 .

[34]  F. W. Fowler,et al.  The N-acyl-.alpha.-cyano-1-azadienes. Remarkably reactive heterodienes in the Diels-Alder reaction , 1990 .

[35]  D. Boger,et al.  Diels-Alder reactions of 1-aza-1,3-butadienes: room temperature, endo-selective LUMOdiene-controlled [4 + 2] cycloaddition reactions of N-sulfonyl-4-(ethoxycarbonyl)-1-aza-1,3-butadienes , 1990 .

[36]  D. Boger,et al.  Room-temperature, endo-specific 1-aza-1,3-butadiene Diels-Alder reactions: acceleration of the LUMOdiene-controlled [4 + 2] cycloaddition reactions through noncomplementary aza diene substitution , 1990 .

[37]  D. Boger,et al.  A general solution to implementing the 4.pi. participation of 1-aza-1,3-butadienes in Diels-Alder reactions: inverse electron demand Diels-Alder reactions of .alpha..beta.-unsaturated N-benzenesulfonyl imines , 1989 .

[38]  F. W. Fowler,et al.  The Diels-Alder reaction of 1-azadienes. The effect of an α-cyano substituent , 1989 .

[39]  F. J. Pulido,et al.  Synthesis of Z-β-siloxyacrylonitriles and study of their dienophilic properties , 1986 .

[40]  K. Kanematsu,et al.  Reagent design and study of allene as a promising class of reagents (synthons) for cycloaddition. The site selective and regioselective Diels-Alder reactions of (phenylsulfonyl)propadiene and alkylation of the adducts , 1985 .

[41]  D. Pasto.  Recent developments in allene chemistry , 1984 .

[42]  C. Shieh,et al.  Halogenated ketenes. 38. Cycloaddition of .alpha.,.beta.-unsaturated imines with ketenes to yield both .beta.- and .delta.-lactams , 1983 .

[43]  D. Boger.  Diels-Alder reactions of azadienes , 1983 .

[44]  G. Hughes,et al.  Cyanoketenes. Cycloadditions of chlorocyanoketene to α,β-unsaturated imines , 1983 .

[45]  J. Chang,et al.  The observation of zwitterions in the thermal reaction of ketenes with carbon-nitrogen double bonds , 1982 .

[46]  D. Stout,et al.  Recent advances in the chemistry of dihydropyridines , 1982 .

[47]  F. Bossert,et al.  4‐Aryldihydropyridines, a New Class of Highly Active Calcium Antagonists , 1981 .

[48]  D. Pasto.  Reinterpretation of the mechanisms of concerted cycloaddition and cyclodimerization of allenes , 1979 .

[49]  J. Kuthan,et al.  Chemistry of dihydropyridines , 1972 .

[50]  R. Gompper,et al.  Detection of Dipoles in Cycloadditions to Allenes , 1971 .

[51]  M. Saunders,et al.  The Preparation of N-Phenyl-1,2-dihydropyridine1,2 , 1962 .