Abstract
Cross-coupling reaction of bis(pinacolato)diboron with β-(trifluoromethanesulfonyloxy)-α,β-unsaturated
carbonyl compounds was carried out in the presence of PdCl2 (PPh3 )2 -2PPh3 (3 mol%)
and KOPh in toluene or K2 CO3 in dioxane for
the synthesis of cyclic and acyclic β-boryl-α,β-unsaturated
esters, amides, and ketones in high yields.
Key words
diboron - vinyl triflate - palladium - cross-coupling - catalysis
References
1 Vaultier M.
Lorvelec G.
Plunian B.
Paulus O.
Bouju P.
Mortier J. In
Contemporary
Boron Chemistry
Davidson AK.
Hughes AK.
Marder TB.
Wade K.
The
Royal Society of Chemistry;
Cambridge:
2000.
p.464
2a Davies CD.
Marsden SP.
Stokes ESE.
Tetrahedron
Lett.
1998,
39:
8513
2b Davies CD.
Marsden SP.
Stokes ESE.
Tetrahedron Lett.
2000,
41:
4229
2c Farthing CN.
Marsden SP.
Tetrahedron
Lett.
2000,
41:
4235
3 Fontani P.
Carboni B.
Vaultier M.
Maas G.
Synthesis
1991,
605
4 Guennouni N.
Lhermitte F.
Cochard S.
Carboni B.
Tetrahedron
1995,
51:
6999
5 Negishi E.-i.
Yoshida T.
J. Am. Chem. Soc.
1973,
95:
6837
6 Jehanno E.
Vaultier M.
Tetrahedron Lett.
1995,
36:
4439
7a Marcuccio SM, Rodopoulos M, and Weigold H. inventors; WO 9858935
A1.
7b Marcuccio SM.
Rodopoulos M.
Weigold H.
10th International Conference
on Boron Chemistry
University of Durham;
England:
July
1999.
p.PB-35
8 Ishiyama T.
Miyaura N.
J. Organomet. Chem.
2000,
611:
392
9a Ishiyama T.
Murata M.
Miyaura N.
J. Org. Chem.
1995,
60:
7508
9b Ishiyama T.
Itoh Y.
Kitano T.
Miyaura N.
Tetrahedron Lett.
1997,
38:
3447
9c Ishiyama T.
Ishida K.
Miyaura N.
Tetrahedron
2001,
57:
9813
10a Takahashi K.
Takagi J.
Ishiyama T.
Miyaura N.
Chem.
Lett.
2000,
126
10b Takagi J.
Takahashi K.
Ishiyama T.
Miyaura N.
J. Am. Chem. Soc.
2002,
124:
8001 ; and difficulties to apply the reaction
conditions used for the borylation of aryl electrophiles to that
of vinyl electrophiles have been described therein
11a Ishiyama T.
Ahiko T.-a.
Miyaura N.
Tetrahedron Lett.
1996,
37:
6889
11b Ahiko T.-a.
Ishiyama T.
Miyaura N.
Chem.
Lett.
1997,
811
12 Ishiyama T.
Oohashi Z.
Ahiko T.-a.
Miyaura N.
Chem. Lett.
2002,
780
13a Nöth H.
Z. Naturforsch.
1984,
39b:
1463
13b Ishiyama T.
Murata M.
Ahiko T.-a.
Miyaura N.
Org. Synth.
2000,
77:
176
14a Stang PJ.
Hanack M.
Subramanian LR.
Synthesis
1982,
85
14b Ritter K.
Synthesis
1993,
735
15 Subramanian LR.
Hanack M.
Chang LWK.
Imhoff MA.
Schleyer PvR.
Effenberger F.
Kurtz W.
Stang PJ.
Dueber TE.
J. Org. Chem.
1976,
41:
4099
16 A representative procedure for 3 : A flask placed with PdCl2 (PPh3 )2 (0.03
mmol), PPh3 (0.06 mmol), pin2 B2 1 (1.1 mmol), and KOPh or K2 CO3 (1.5
mmol) was flushed with nitrogen. Toluene or dioxane (6 mL) and ethyl
2-(trifluoromethanesulfonyloxy)-1-cyclohexenecarboxylate (1.0 mmol)
were then added. The resulting mixture was stirred at 50 °C
or 80 °C for the period shown in Table
[2 1 H NMR
(400 MHz, CDCl3 , TMS) δ 1.27 (t, 3 H, J = 7.2 Hz), 1.33 (s, 12 H),
1.55-1.65 (m, 4 H), 2.20-2.25 (m, 4 H), 4.21 (q,
2 H, J = 7.2 Hz); 13 C
NMR (100 MHz, CDCl3 , TMS) δ 14.25, 21.42, 21.85,
24.12, 24.77, 27.93, 60.70, 83.34, 134.24, 169.19; HRMS, Found: m/z , 280.1846. Calcd for C15 H25 BO4 :
M+ , 280.1846.
17a Miyaura N.
Suzuki A.
Chem. Rev.
1995,
95:
2457
17b Suzuki A. In
Metal-Catalyzed Cross-Coupling Reactions
Diederich F.
Stang PJ.
Wiley-VCH;
Weinheim:
1998.
p.49
17c Miyaura N.
Top.
Curr. Chem.
2002,
219:
11
18a Zargarian D.
Alper H.
Organometallics
1991,
10:
2914
18b Arcadi A.
Cacchi S.
Fabrizi G.
Moro L.
Eur. J. Org. Chem.
1999,
1137
19 The 1,3-dienes 7 shown
in Table
[3
