名称:
Synthesis of 2,3,4,6-Tetra-substituted Pyridines from N-Silyl-1-aza-allyl Anions and 1,3-Diphenyl-2-propen-1-one
摘要:
The reaction of N-silyl-1-aza-allyl anions (3) with 1,3-diphenyl-2-propen-1-one (4) is described. The anions (3a-f), which were prepared from an alpha-silyl carbanion of 3-methyl-5-trimethylsilylmethylisoxazole (1a) [or 2-trimethyl-silylmethylpyridine (1b)] and p-substituted benzonitriles (2a-e, R-1 = H, p-Me, pOMe, p-Cl, p-CF3), reacted with a slightly excess amount of 1,3-diphenyl-2-propen-1-one (4) to afford 2,3,4,6-tetra-substituted pyridine derivatives (5a-f) in good yields. But the analogous reaction of the anion (3e) with cinnamaldehyde or methyl vinyl ketone did not give the corresponding pyridines.