Silylene Reactions with N-Methylpyrrole:  Cycloadditions and Rearrangements^1,2

Abstract

, generated by photolysis of hexa-tert-butylcyclotrisilane, reacts with Nmethylpyrrole possibly via an intermediate 7). On heating, 7 rearranges by an electrocyclic reaction to provide the correspondingly substituted 1-aza-2-silacyclohexa-3,5diene 8. Further treatment of 7 with 2 gives, presumably through a tricyclic compound, the final product 2,2,5,5tetra-tert-butyl-1-methyl-1-aza-2,5-disilacyclohepta-3,6diene (10), which was characterized by an X-ray structure analysis.

5.16 Cyclobutene Ring Opening Reactions

“…69 Di-tert-butylsilylene, generated by photolysis, reacted with N-methylpyrrole to furnish 2-aza-3-silabicyclo[2.2.0]hex-5-ene 144 (Scheme 60). 70 The thermal conversion of cyclobutadiene dimer, tricyclo[4.2.0.0 2,5 ]octa-3,7-diene, to cyclooctatetraene was first reported in 1975. 72 tert-Butylacetylene underwent regioselective tetramerization in the presence of AlBr 3 and Et 3 N to afford the cyclobutadiene dimer 149 (Scheme 62).…”

3-Silaazetidine: An Unexplored yet Versatile Organosilane Species for Ring Expansion toward Silaazacycles

“…These small-ring silacycles have been extensively studied in main-group chemistry and have found numerous applications in organic synthesis. However, silaazetidines, including 2-silaazetidine − and 3-silaazetidine, bearing both Si and N atoms are some of the exceptions (Scheme , left). The synthesis, particularly for 3-silaazetidine, is extremely challenging and only a very few analogues − have been prepared.…”