Pergamon PII: S0040-4020(97)00100-2 Tetrahedron, Vol. 53, No. 10, pp. 3795-3804, 1997 © 1997 Published by Elsevier Science Ltd All rights reserved. Printed in Great Britain 0040-4020/97 $17.00 + 0.00 Regioselective Electrophilic Alkylation of Anilines with Phenylacetylene in the Presence of Montmorillonite KSF. Attilio Arienti, Franca Bigi, Raimondo Maggi, Elena Marzi, Pietro Moggi, Massimo Rastelli, Giovanni Sartori* and Fabio Tarantola. Dipartimento di Chimica Organica e lndustriale dell'Universit& Viale delle Scienze, 1-43100 Parma, Italy. Abstract: Substituted anilines react with phenylacetylene in the presence of montmorilionite KSF affording I.l-diarylethylenes 3 in good yields and excellentselectivities. In the presenceof an excess of phenylacetylene, para-toluidine and para-anisidine give the corresponding 2,6-bis(l-phenyl- vinyl)anilines. © 1997 Published by Elsevier Science Ltd. All rights reserved. Introduction The electrophilic C-alkylation of aromatic amines with reagents containing carbon-carbon multiple bonds represents an important and a not easily accessible process. Indeed, the normal activating effect of the amino group is often reversed by complex formation with the acid catalyst. Thus, these compounds cannot generally be C-alkylated under normal Friedel-Crafts conditions~ and some special methodologies were needed to perform the reaction. For example, Kolka early reported the direct ortho-alkylation of aromatic amines with alkenes in the presence of aluminium anilides.2 Some few other catalysts were also described as effective promoters of the reaction. These include activated clays, silica-alumina, zeolites and COC12 or CdCI2 salts of anilines.3 Moreover, ortho-allylarylarffmes were synthesised via amino-Claisen rearrangement of aromatic N-allylamines. 4 To the best of our knowledge, no C-alkylation of aromatic amines with alkynes has been described. The literature reports only few examples of the synthesis of enamines by N-alkylation of anilines with phenylacetylene.5 In conjunction with our research program concerning the use of solid acids in fine chemicals preparation, 6 we were intrigued with the possibility of obtaining direct C-alkylation of aromatic amines with alkynes over commercially available heterogeneous catalysts. 3795