Abstract
The reaction of o -acyl-N -tosylanilines with lithium trimethylsilyldiazomethane followed by treatment with t -BuLi and then electrophiles gave 2,3-disubstituted N -tosylindoles in a one-pot process.
Key words
o -acylanilines - alkylidenecarbene - indoles - lithium trimethylsilyldiazomethane - one-pot synthesis
References
1a Pindur U.
Adam R.
J. Heterocycl. Chem.
1988,
25:
1
1b Gribble GW.
J. Chem. Soc., Perkin Trans. 1
2000,
1045
2 Miyagi T.
Hari Y.
Aoyama T.
Tetrahedron Lett.
2004,
45:
6303
3 Collins MA.
Tanis SP.
Encyclopedia of Reagents for Organic Synthesis, Vol. 5
Paquette LA.
John Wiley & Sons;
Chichester:
1995.
p.2992
4 Though the synthesis of 2,3-disubstituted N -tosylindoles from 2 was reported, the method requires three steps and the substituent at the 2-position is limited to acyl, ester or cyano groups.10
5 When the synthesis of 5a from 2a was carried out by standard step-wise procedure, the overall yield of 5a was ca. 70%.
6 Ames DE.
J. Chem. Soc.
1964,
1763
7 Fryer RI.
Winter D.
Sternbach LH.
J. Heterocycl. Chem.
1967,
4:
355
8 Goujon J.-YG.
Zammattio F.
Chrétien J.-M.
Beaudet I.
Tetrahedron
2004,
60:
4037
9a Kikugawa Y.
Synthesis
1981,
461
9b Yamane M.
Kubota Y.
Narasaka K.
Bull. Chem. Soc. Jpn.
2005,
78:
331
10 Jones CD.
J. Org. Chem.
1972,
37:
3624
