1.3,2-diazastanna-[3]ferrocenophanes bearing alkyn-1-yl groups at tin and their 1,1-organoboration with triethylborane-molecular structure of a novel spirotin compound

2,2-Dichloro-1,3-bis(trimethylsilyl)-1,3,2-diazastanna-[3]ferrocenophane (3) reacts with lithium alkynides LiCequivalent toCR(1) to give the corresponding di(alkyn-1-yl)tin derivatives 4a (R-1 = Bu-t) and 4b (R-1 = SiMe3). 1,1-Organoboration of 4 with triethylborane affords the spirotin compounds 5 which contain both a ferrocenophane and a stannacyclopentadiene ring. The crystal structure of 5b was determined by X-ray analysis. The compounds 4 and 5 were characterised in solution by multinuclear magnetic resonance (H-1-, B-11-, C-13-, N-15-, Si-29-, Sn-119-NMR), using pulsed field gradients in HMBC experiments for the H-1 detected N-15- and Sn-119-NMR signals. The compound 5b was also studied by solid-state C-13, Si-29 and Sn-119 MAS NMR in order to correlate liquid and solid-state NMR data with the structural evidence. (C) 2003 Elsevier Science B.V. All rights reserved.