NMR SPECTROSCOPY OF ORGANOLITHIUM COMPOUNDS .19. REACTION OF (Z)-1,2-BIS(TRIMETHYLSILYL)-1-PHENYLETHENE WITH LITHIUM - DIANION FORMATION, SCHLENK DIMERIZATION, AND C-13,LI-6 COUPLING IN A BENZYLLITHIUM SYSTEM

摘要

Lithium reduction of (Z)-1,2-bis(trimethylsilyl)-1-phenylethene (1) yields the dianion of the (E)-isomer (3) and via Schlenk dimerization dilithium 1,4-diyl-1,4-diphenyl-1,2,3,4-tetrakis(trimethylsilyl)butane (4). The NMR parameters for both systems are reported and their solution structures are discussed. The formation of 4 is reversible and a unique feature of 4 is the scalar (1)J(C-13,Li-6) spin-spin coupling constant of 2.7 Hz for the C-Li bond, which is resolved even at room temperature. Copyright (C) 1996 Elsevier Science Ltd [References: 25]