Process for the preparation of an indene and use thereof for the preparation of metallocenes

摘要

Production of indenes of formula (I) or(II) comprises (a) conversion of a 2-substituted benzyl halide into the corresponding disubstituted malonic acid diester by reaction with a suitable malonate diester, (b) hydrogenation and decarboxylation of the diester, (c) conversion of the carboxylic acid into its acid chloride followed by ring closure to the 1-indanone and (d) reduction to the indene with loss of water. R<3> = halogen, optionally halogenated 1-10C alkyl, 6-10C aryl, NR<10>2, SR<10>, OSiR<10>3 or PR<10>3; R<10> = halogen, 1-10C alkyl or 6-10C aryl; R<5> = as for R<3>. Also claimed are (i) indenes (I) and (II) and (ii) 1-indanones of formula (IV). Also claimed is the use of (IV) for the production of indenes as above.