A facile synthesis of functionalized 4-benzylpyridines by using mixed copper, zinc benzylic organometallics

Preparation and reactions of polyfunctional organozinc reagents in organic synthesis

“…106 The allylic zinc compound 121 formally allows (3 + 2) cyclization reactions to be performed,167 and its addition to aldehydes or imines furnishes, after a Pd(0)-catalyzed ring closure, 3-methylenetetrahydrofurans and 3-methylenepyrrolidines (eq 86). 167 In the presence of Lewis acids such as Ti(Oi-Pr)"Cl4_n,158-169 MeaSiCl, or BFg-OEta,40 the addition of functionalized organozinc halides to aldehydes proceeds satisfactorily. An excellent chemoselectivity is observed; thus, the reaction of cinnamaldehyde with the zinc-copper reagent 122 produces in the presence of BF3*OEt2 (2 equiv) the 1,2-adduct 123 in 89% yield (Table 14), whereas in the presence of Me3SiCl (2 equiv) the same organometallic reagent undergoes a 1,4addition leading to the aldehyde 124 (92% yield; eq 87).…”

Synthesis of 4‐Arylpyridines Containing Electron‐Withdrawing Groups on the Benzene Ring

“…All compounds gave satisfactory analytical and spectral data. 4-(4·cyanophenyl) 8.53 (d,1H,J = 5.0 Hz,7.77 (dd,2H,J = 1.8,8.4 Hz,ary12H),7.49 (dd,2H,J = 1.8,8.4 Hz, aryl2H), 7.15 (d, JR, J ::= 5.0 Hz., pyridyl H-5), 2.29 (5,3H,Me); IR (CHCh) 2989, 2980, 2231::N), 1588, 1480, 1400, 1203MS mlz 194 (M+, 100),166 (15), 140 (12), 83 (11), 71 (13); Anal. Calcd for C13H 10Nz: C,80.38;H,5.19;N,14.42,Found: C,…”

“…The regioselective synthesis of 4-arylpyridines l -6 by using l-(cthoJ..)'Carbonyl)pyridinium ch1oride 7 n and aryl Grignard reagents or aryllithiums in the presence of copper(I) iodide was reported from our laboratory.f This method was applied to the synthesis of several condensed tricyclic pyridines. 13 -14 We found also that mixed copper, zinc benzylic organometallics can be added to pyridinium salts to obtain functionalized 4-benzylpyridines in a regiod h I · [15][16] A I' [17][18] an c emose ecnve manner. iterature survey shows scanty information for the synthesis of 4-arylpyridines containing electron-withdrawing groups on the benzene ring.…”

Synthesis and mesomorphic studies on the series of 2-(4-alkoxyphenyl)-5-phenylpyridines and 2-(6-alkoxynaphthalen-2-yl)-5-phenylpyridines

“…Previously, we successfully applied the regioselective addition of organometallic reagents to 1-acylpyridinium salts for the preparation of some pyridine-containing compounds [22][23][24]. Recently, we reported the novel synthesis of some homologous series of pyridine-containing liquid crystalline compounds [25][26][27][28].…”