PROCESS FOR SYNTHESIS OF INDENES

摘要

The present invention relates to a new process for the synthesis of 2,3,4,5,6,7-substituted indenes, which are useful precursors for the formation of certain ansa-metallocene catalysts.

主权项

1. A process for the preparation of a compound of the formula I shown below:wherein:
R1 and R2 are each (1-10C)alkyl;and wherein the process comprises the steps of:
(i) reacting a compound of formula A: wherein R1 and R2 are each as defined above;with a chlorinating or brominating agent to form a compound of formula B: wherein R1 and R2 are each as defined above and X is chloro or bromo;and adding 1,2,3,4-tetramethylbenzene and a Lewis acid catalyst to the reaction mixture to react with compound B to form a compound of formula C: wherein R1 and R2 are each as defined above; (ii) reacting the compound of formula C with a solution of a hydride transfer reagent followed by adding a dehydrating agent to the reaction mixture to form a compound of Formula I.