Cycloaddition reaction of 2-azadienes derived from beta-amino acids with electron-rich and electron-deficient alkenes and carbonyl compounds. Synthesis of pyridine and 1,3-oxazine derivatives.
Functionalized keto-enamines 6 were obtained by nucleophilic addition of enol ethers to the imine moiety of 2-azadienes derived from dehydroaspartic esters 4. Reactions of 2-azadiene 4c containing three electron-withdrawing substituents (CO(2)R) with enol ethers 5 in the presence of lithium perchlorate led to the formation of tetrahydropyridine derivatives 7 in a regio- and stereoselective fashion. 2H-[1,3]-oxazines 10 and pyridine derivatives 12 and 13 were obtained by heterocycloaddition reactions of electron-poor azadienes 4d-g containing two electron-withdrawing substituents (4-O(2)N-C(6)H(4), CO(2)R) in positions 1 and 4 with carbonyl derivatives (ethyl glyoxalate 9a and diethyl ketomalonate 9b) and the electron-deficient olefin tetracyanoethylene 11.
Palacios
Francisco
F
Departamento de Química Orgánica, Facultad de Farmacia, Universidad del País Vasco, Vitoria, Spain. qoppagaf@vf.ehu.es
Herrán
Esther
E
Rubiales
Gloria
G
Ezpeleta
Jose María
JM
D000475:Alkenes / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry*; D001372:Aza Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D004563:Electrochemistry / Q000379:methods; D004987:Ethers / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D018020:Lithium Compounds; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010078:Oxazines / Q000138:chemical synthesis / Q000737:chemistry; D010472:Perchlorates; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry; D013055:Spectrophotometry, Infrared
D000475:Alkenes; D000596:Amino Acids; D001372:Aza Compounds; D004987:Ethers; D007659:Ketones; D018020:Lithium Compounds; D010078:Oxazines; D010472:Perchlorates; D011725:Pyridines; C054684:lithium perchlorate