Abstract
The readily available, heterogeneous, and inexpensive catalyst
nickel-on-charcoal (Ni/C) can be used to mediate couplings between
vinyl alanes and benzylic chlorides under very mild conditions and
in good yields. Although such allylated aromatics are themselves
important compounds, as demonstrated in this work, their syntheses
under the ‘green chemistry’ conditions used can smoothly
arrive at precursors to valued quinone natural products, such as
the nutraceutical coenzyme Q10 .
Key words
heterogeneous catalysis - nickel-on-charcoal - cross-couplings - allylated aromatics - coenzyme Q10
References 1 Lipshutz, B. H.; Mollard, P.; Pfeiffer,
S. S.; Chrisman, W., submitted.
homogeneous conditions, see:
2a Lipshutz BH.
Kim S.-K.
Mollard P.
Stevens KL.
Tetrahedron
1998,
54:
6999
2b Lipshutz BH.
Bulow G.
Stevens KL.
Lowe R.
Tetrahedron
1996,
52:
7265
3 Lipshutz BH.
Adv.
Synth. Catal.
2001,
343:
313
4a Lipshutz BH.
Blomgren PA.
J. Am. Chem. Soc.
1999,
121:
5819
4b Lipshutz BH.
Tomioka T.
Blomgren PA.
Sclafani JA.
Inorg.
Chim. Acta
1999,
296:
164
4c Lipshutz BH.
Sclafani JA.
Blomgren PA.
Tetrahedron
2000,
56:
2139
4d Lipshutz BH.
Ueda H.
Angew. Chem.,
Int. Ed.
2000,
39:
4492 ; Angew. Chem. 2000 , 112 , 4666
4e Lipshutz BH.
Tomioka T.
Sato K.
Synlett
2001,
970
5a Van Horn DE.
Negishi E.
J.
Am. Chem. Soc.
1978,
100:
2252
5b Negishi E.
Van Horn DE.
Yoshida T.
J. Am.
Chem. Soc.
1985,
107:
6639
5c Matsushita H.
Negishi E.
Org. Synth.
1984,
63:
31
5d Negishi E.
Pure Appl.
Chem.
1981,
53:
2333
6 Lipshutz BH.
Tasler S.
Adv. Synth. Catal.
2001,
343:
327
7 Inductively
Coupled Plasma Mass Spectrometry
Montaser A.
Wiley-VCH;
New York:
1998.
8 Lipshutz, B. H.; Tasler, S.; Chrisman,
W.; Spliethoff, B.; Tesche, B. J. Org. Chem .
in press.
