Representative aryl, vinyl and alkynyl bromides undergo efficient Pd-catalyzed cross coupling with trans-1-(9-borabicyclo[3.3.1]non-9-yl)-2-(trimethylsilyl)ethene (1) under basic conditions to produce the corresponding trans styryl-, dienyl- and enynylsilanes (58–89%).
The dialkylaluminum hydride-promoted reaction of 1-silylalk-3-en-1-ynes gave symmetrical 1,2,3,5-tetrasubstituted benzenes as single regiolsomers. The novel cyclodimerization via skeletal rearrangement can be rationalized by an unprecedented mechanism Involving sequential hydroalumination, alkene isomerization, carboalumination, carbon-carbon bond cleavage, and retro-hydroalumination.
Stereospecific synthesis of (1E,3Z)- and (1E,3E)-1-trimethylsilyl-1,3- dienes by means of sequential cross-coupling reactions