A highly efficient synthesis of ( Z )‐1‐aryl‐2‐silyl‐1‐ stannylethenes and their conversion to ( E )‐2‐ arylethenyl‐, ( Z )‐2‐(2‐pyridyl)ethenyl‐ and allenyl‐silanes

A Pd(dba) 2 –P(OEt) 3 combination allowed the silastannation of arylacetylenes, 1‐hexyne or propargyl alcohols with tributyl(trimethylsilyl)stannane to take place at room temperature, producing ( Z )‐2‐silyl‐1‐stannyl‐1‐substituted ethenes in high yields. Novel silyl(stannyl)ethenes were fully characterized by 1 H‐, 13 C‐, 29 Si‐ and 119 Sn‐NMR as well as infrared and mass analyses. Treatment of a series of ( Z )‐1‐aryl‐2‐silyl‐1‐stannylethenes and ( Z )‐1‐(3‐pyridyl)‐2‐silyl‐1‐stannylethene with hydrochloric acid or hydroiodic acid in the presence of tetraethylammonium chloride (TEACl) or tetrabutylammonium iodide (TBAI) led to the exclusive formation of ( E )‐trimethyl(2‐arylethenyl)silanes with high stereoselectivity. A similar reaction of ( Z )‐1‐(2‐anisyl)‐2‐silyl‐1‐stannylethene also produced E ‐type trimethyl[2‐(2‐anisyl)ethenyl]silane, while ( Z )‐trimethyl [2‐(2‐pyridyl)ethenyl]silane was produced exclusively from (Z)‐1‐(2‐pyridyl)‐2‐silyl‐1‐stannylethene. Protodestannylation of ( Z )‐1‐[hydroxy(phenyl)methyl]‐2‐silyl‐1‐stannylethene with trifluoroacetic acid took place via the β‐elimination of hydroxystannane, providing trimethyl(3‐phenylpropa‐1,2‐dienyl)silane quite easily. The destannylation products were also fully characterized. Copyright © 2007 John Wiley & Sons, Ltd.