FORMATION OF ACETYLENIC-COMPOUNDS AND RING TRANSFORMATIONS OF 3-ALKYL-3-FERROCENYLCYCLOPROPENES IN THE REACTION WITH 1,3-DIPHENYLISOBENZOFURAN

The reaction of 3-ferrocenyl-3-methylcyclopropene with 1,3-diphenyliso benzofuran leads to the formation of exo- and endo poxy-2-ethynyl-2-fe rrocenyl-1,4-diphenyltetralines as the main products in addition to th e isomeric Diels - Alder exo-adducts. At the same time, 3-tert-butyl- and 3-(1-adamantyl)-3-ferrocenylcyclopropenes form the endo- and exo-a dducts of 3-alkyl-1,2-(1-propene-1,3-diyl)ferrocene. The structures of the acetylenic compounds and of the adduct containing a Bu-t-substitu ent are established by X-ray structural analysis. A possible reaction pathway via intermediate zwitter-ion is discussed. (C) 1998 Elsevier S cience S.A. All rights reserved.