Synthesis and Molecular Structure of Silole Derivatives Bearing Functional Groups on Silicon: 1,1‐Organoboration of Dialkynylsilanes

Various dialkynylsilanes bearing Si–H or SiCl functions in addition to the alkynyl groups react with an excess of triethylborane after heating at 100–110 °C for several days via slow intermolecular 1,1‐ethylboration followed by fast intramolecular 1,1‐vinylboration to give Si‐functional substituted siloles. Similarly, the reactions with 9‐ethyl‐9‐borabicyclo[3.3.1]nonane afford polycyclic compounds containing the silole ring. Protodeborylaton with an excess of acetic acid leads to simultaneous substitution of BEt 2 and Si–H functions to give 1‐acetoxysiloles. All new siloles were characterized by NMR spectroscopy in solution ( 1 H, 11 B, 13 C, 29 Si NMR), and for one example of a polycyclic silole derivative the molecular structure was determined by X‐ray analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)