Abstract
A wide range of polyfunctional aryl, heteroaryl, alkyl, and benzylic
zinc reagents were coupled with unsaturated aryl halides bearing
an acidic NH or OH proton, using palladium(II) acetate (1 mol%),
and S-Phos (2 mol%) as catalyst without the need of protecting groups.
Key words
palladium catalysis - cross-coupling - functionalized
zinc reagents - polyfunctional biaryls
References
1a Metal-Catalyzed Cross-Coupling Reactions
2nd
ed.:
de Meijere A.
Diederich F.
Wiley-VCH;
Weinheim:
2004.
1b Tsuji J.
Transition Metal Reagents and Catalysis: Innovations
in Organic Synthesis
Wiley;
Chichester:
1995.
1c Transition
Metals for Organic Synthesis
2nd ed.:
Beller M.
Bolm C.
Wiley-VCH;
Weinheim:
2004.
2a Miyaura N.
Suzuki A.
Chem.
Rev.
1995,
95:
2457
2b Littke AF.
Fu GC.
Angew.
Chem. Int. Ed.
1998,
37:
3387
2c Wolfe JP.
Buchwald SL.
Angew.
Chem. Int. Ed.
1999,
38:
2413
2d Zapf A.
Ehrentraut A.
Beller M.
Angew.
Chem. Int. Ed.
2000,
39:
4153
2e Molander GA.
Biolatto B.
J. Org.
Chem.
2003,
68:
4302
3a Handy ST.
Zhang Y.
Bregman H.
J. Org. Chem.
2004,
69:
2362
3b Chaumeil H.
Signorella S.
Le Drian C.
Tetrahedron
2000,
56:
9655
3c Wanatabe T.
Miyaura N.
Suzuki A.
Synlett
1992,
207
4a Negishi E.
Valente LF.
Kobayashi M.
J. Am. Chem. Soc.
1980,
102:
3298
4b Negishi E.
Acc.
Chem. Res.
1982,
15:
340
4c Zeng X.
Quian M.
Hu Q.
Negishi E.
Angew. Chem. Int. Ed.
2004,
43:
2259
5a Sase S.
Jaric M.
Metzger A.
Malakhov V.
Knochel P.
J.
Org. Chem.
2008,
73:
7380
5b Gavryushin A.
Kofink C.
Manolikakes G.
Knochel P.
Org. Lett.
2005,
7:
4871
6 Manolikakes G.
Schade MA.
Muñoz Hernandez C.
Mayr H.
Knochel P.
Org.
Lett.
2008,
10:
2765
7a Altman RA.
Buchwald SL.
Nature Protocols
2007,
2:
3115
7b Barder TE.
Buchwald SL.
J.
Am. Chem. Soc.
2007,
129:
5096
7c Milne JE.
Buchwald SL.
J. Am.
Chem. Soc.
2004,
126:
13028
7d Barder TE.
Walker SD.
Martinelli JR.
Buchwald SL.
J.
Am. Chem. Soc.
2005,
127:
4685
8 Krasovskiy A.
Malakhov V.
Gavryushin A.
Knochel P.
Angew. Chem. Int. Ed.
2006,
45:
6040
9 Typical pK
a values
(in DMSO) for anilines range between 20-30; for a comprehensive
compilation of pK
a data see http://www.chem.wisc.edu/areas/reich/pkatable/index.htm and
references cited therein.
10 Magnetic Properties of Organic Materials
Lathi PM.
Marcel Dekker;
New
York:
1999.
11 Metzger A.
Schade MA.
Knochel P.
Org.
Lett.
2008,
10:
1107
12 Our experiments indicate a relative
kinetic basicity of zinc reagents: arylzinc halide > alkylzinc
halide > benzylic zinc halide. For further experimental
details, see ref. 7.
13 Krasovskiy A.
Knochel P.
Synthesis
2006,
890
