Preparation of cyclopenta-heterocycles, useful for preparing metallocene catalysts for olefin polymerization, by reacting heterocycle with unsaturated carboxylic acid in presence of strong acid and dehydrating agent

摘要

Method for preparing cyclopenta(b) 5-membered heterocyclic ketones (I)/(Ia) by reacting a 5-membered heterocycle with an alpha,beta-unsaturated carboxylic acid (III), or its anhydride, in a liquid medium containing an organic acid stronger than (III) and a water-absorbing agent (A). Method for preparing cyclopenta(b) 5-membered heterocyclic ketones of formulae (I) or (Ia) by reacting a 5-membered heterocycle (II) with an alpha,beta-unsaturated carboxylic acid of formula, or its anhydride in a liquid medium containing an organic acid stronger than (III) and a water-absorbing agent (A). R3-C(=CH2)-COOH (III) (R3-C(=CH2)CO)2O (IV) R1 and R2 = H or 1-40C hydrocarbyl, or together form a ring; R3 = 1-40C hydrocarbyl; X = element of group 16 of the Periodic System or NR4; R4 = electron-withdrawing group, i.e. 1-40C perfluorohydrocarbyl or organosulfonyl