RSS-Feed abonnieren
DOI: 10.1055/s-0030-1261183
Regioselective 1,6-Conjugate Addition of Boronic Acids and Grignard Reagents to Dienylpyridines
Publikationsverlauf
Publikationsdatum:
12. August 2011 (online)

Abstract
Functionalization of the lateral chain of dienylpyridines was achieved by the regioselective 1,6-addition of boronic acids catalyzed by rhodium(I) or Grignard reagents under iron(II) catalysis.
Key words
addition - catalysis - pyridines - rhodium - iron
- See, for example:
- 1a
Hoffman A.Farlow MW.Fuson RC. J. Am. Chem. Soc. 1933, 55: 2000MissingFormLabel - 1b
Gilman H.Gainer GC. J. Am. Chem. Soc. 1949, 71: 2327MissingFormLabel - 1c
Mathis C.Hogen-Esch TE. J. Am. Chem. Soc. 1982, 104: 634MissingFormLabel - 1d
Dryanska V.Ivanov C. Synthesis 1983, 143MissingFormLabel - 1e
Houpis IN.Lee J.Dorziotis I.Molina A.Reamer B.Volante RP.Reider PJ. Tetrahedron 1998, 54: 1185MissingFormLabel - 1f
Dondoni A.Fantin G.Fogagnolo M.Medici A.Pedrini P. Tetrahedron 1988, 44: 2021MissingFormLabel - 1g
Clariana J.Gálvez N.Marchi C.Moreno-Mañas M.Vallribera A.Molins E. Tetrahedron 1999, 55: 7331MissingFormLabel - 1h
Baschieri A.Bernardi L.Ricci A.Suresh S.Adamo MFA. Angew. Chem. Int. Ed. 2009, 48: 9342MissingFormLabel - 1i
Mineyama K.Maekawa H.Kohsaka A.Yamamoto Y.Nishiguchi I. Tetrahedron 2009, 65: 7706MissingFormLabel - 1j
Sun H.-W.Liao Y.-H.Wu Z.-J.Wang H.-Y.Zhang X.-M.Yuan W.-C. Tetrahedron 2011, 67: 3991MissingFormLabel - 2a
Lautens M.Roy A.Fukuoka K.Fagnou K.Martin-Matute B. J. Am. Chem. Soc. 2001, 123: 5358MissingFormLabel - 2b
Amengual R.Michelet V.Genêt J.-P. Tetrahedron Lett. 2002, 43: 5905MissingFormLabel - 3a
Pattison G.Piraux G.Lam HW. J. Am. Chem. Soc. 2010, 132: 14373MissingFormLabel - 3b
Kobayashi T.Yorimitsu H.Oshima K. Chem. Asian J. 2010, 6: 669MissingFormLabel - 4
Csákÿ AG.de la Herrán G.Murcia MC. Chem. Soc. Rev. 2010, 39: 4080 - 5 For the synthesis of starting materials
(1) from 2-methyl-pyridine, see:
Braun M.Mroß S.Schwarz I. Synthesis 1998, 83 - 7a
Fukuhara K.Urabe H. Tetrahedron Lett. 2005, 46: 603MissingFormLabel - 7b
Okada S.Arayama K.Murayama R.Ishizuka T.Hara K.Hirone N.Hata T.Urabe H. Angew. Chem. Int. Ed. 2008, 47: 6860MissingFormLabel
References and Notes
Recovery of starting material was observed when treating 1a with PhB(OH)2 using [Rh(cod)]2BF4 or [Rh(cod)Cl]2 as catalysts (5 mol%) in the presence of Ba(OH)2, K3PO4, or KOH (1.0 equiv) at 50 ˚C in dioxane-H2O (4:1) for 18 h.
8Recovery of starting material was observed when treating 1a with PhMgBr in THF in the presence of CuI (10 mol%) or in the absence of catalyst at r.t. for 18 h.
9
Typical Procedure
for the Addition of Grignard Reagents to Dienylpyridines (1)
Synthesis of (
Z
)-2-[4-(
p
-Methoxyphenyl)-3-methylhex-2-enyl]pyridine
(2m)
To a stirred solution of 1e (86.6
mg, 0.5 mmol) and FeCl2 (6.4 mg, 0.05 mmol) in anhyd
THF (3.5 mL) under Ar was added p-methoxyphenylmagnesium
bromide (1.0 M in THF, 0.9 mmol, 0.9 mL) at 0 ˚C. The solution
was stirred at 0 ˚C for 15 min and at r.t. for 1 h. The
reaction was terminated by the addition of a sat. NH4Cl
aq solution (5 mL). The organic products were extracted with Et2O
(3 × 5 mL). The combined organic layers
were washed with brine, dried over MgSO4, and concentrated
in vacuo. The crude product was chromatographed on silica gel (hexane-EtOAc = 8:2).
¹H NMR
(300 MHz, CDCl3): δ = 8.55 (d, J = 4.7 Hz,
1 H), 7.60 (td, J = 7.7,
1.8 Hz, 1 H), 7.07-7.22 (m, 4 H), 6.82 (dt, J = 8.7, 2.1
Hz, 2 H), 5.55 (t, J = 7.1
Hz, 1 H), 3.72-3.90 (m, 3 H), 3.78 (s, 3 H), 1.66-1.96
(m, 2 H), 1.54 (d, J = 1.0
Hz, 3 H), 0.90 (t, J = 7.3
Hz, 3 H). ¹³C NMR (75 MHz, CDCl3): δ = 12.4,
18.9, 24.2, 36.9, 46.2, 55.3, 113.7 (2 C), 121.2, 122.7, 123.0,
128.7 (2 C), 135.8, 136.6, 139.7, 149.4, 157.9, 161.5.
Determined by NOE measurement upon irradiation of the vinyl-H signal.