Reactivity of Alkoxyethynyl(trimethyl)silane, -germane and -stannane towards Trialkylboranes. Organometallic-Substituted Enol Ethers

Bernd Wrackmeyera, Sergej V. Gruener, Alla S. Zolotareva
2003 Zeitschrift für Naturforschung. B, A journal of chemical sciences  
Methoxyethynyl(trimethyl)silane (1a) reacts at 100°C very slowly with triethylborane (4) to give a mixture of alkenes, one of which is the 1,1-organoboration product (Z)-1-methoxy-1-trimethylsilyl- 2-diethylboryl-but-1-ene (7a). Methoxyethynyl(trimethyl)germane (2a) reacts within minutes at 60 - 70°C with 4, tripropylborane (5) and 9-ethyl-9-borabicyclo[3.3.1]nonane (6) by 1,1-organoboration in the usual regio- and stereospecific way to give the corresponding alkenes (9a - 11a). The analogous
more » ... a). The analogous reactions of the ethoxyethynyl(trimethyl)germane (2b) require longer heating and are accompanied by decomposition of 2b. Ethoxyethynyl(trimethyl)stannane (3b) reacts with the trialkylboranes 4- 6 already below room temperature by 1,1-organoboration to give the alkenes (12b - 14b) in quantitative yield. The compound 3b also reacts with the alkenes, e.g. 9a, 13b, 14b, to give novel organometallicsubstituted dienes. All products were characterised by multinuclear magnetic resonance spectroscopy (1H, 11B, 13C, 29Si, and 119Sn NMR).
doi:10.1515/znb-2003-1101 fatcat:bz5kcq2xrnfldgyhvvl3iqsdwu