THE PREPARATION AND VARIABLE TEMPERATURE H-1 NMR CHARACTERIZATION OF 1-(TRI-N-BUTYLSTANNYL)INDENE, 1-(BU3SN)C9H7

摘要

The synthesis of 1-(tri-n-butylstannyl)indene, 1, was carried out by the reacting lithium indenide with tributylstannyl chloride. The-pale yellow product was collected by distillation in 65% yield, and the procedure is scalable to large quantities. Examination of the room-temperature H-1 NMR spectrum of 1 revealed a fluxional process in which the tributylstannyl group was rapidly interchanging between the 1 and 3 positions on indene. A variable-temperature H-1 NMR study was performed on 1 from -60 degrees C to +40 degrees C and the free energy of activation for the 1,3-interchange was calculated as 15.4 kcal mol(-1) at 60 degrees C, using the Eyring equation. This result is compared to previous studies of the 1,3 migrations of trimethylsilyl and trimethylstannyl groups on indene. (C) 1997 Elsevier Science Ltd. [References: 23]