Tetrahedron letters

Regioselective synthesis of 4-(2-oxoalkyl) pyridines via 1, 4-dihydro-pyridine derivatives using silyl enol ethers and pyridinium salts

K Akiba, Y Nishihara, M Wada

Index: Akiba, Kin-ya; Nishihara, Yoshihiro; Wada, Makoto Tetrahedron Letters, 1983 , vol. 24, # 47 p. 5269 - 5272

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Citation Number: 64

Abstract

Abstract: Trimethylsilyl enol ethers (1) reacted with l-ethoxycarbonylpyridinium chloride (2) at 4-position with high rezoselectivity to afford l-ethoxycarbonyl-4-(2-oxoalkyl)-1, 4_dihydropyridines(2) in 42-8'7% yields. When 2, 2, 2-trichloroethyl chloroformate was employed, yields of the corresponding 1, 4_dihydropyridines(g) were higher (80-100% yields). $ and 8 were oxidized by oxygen or AgN03 to give 4-(2-oxoalkyl) pyridines (1,: 30- ...