Cycloadditions with a Stable Charge‐Separated Cyclobutadiene‐Type Amido‐Substituted Silicon Ring Compound
Jan Keuter, Alexander Hepp, Constantin G. Daniliuc, Milica Feldt, Felicitas Lips
Abstract
Abstract Reductive debromination of {N(SiMe 3 ) 2 }SiBr 3 with Rieke magnesium results in the formation of the five‐vertex silicon cluster with one bromine substituent Si 5 {N(SiMe 3 ) 2 } 5 Br, 1 , and the cyclobutadiene analogue 2 in a 1:1 ratio. The latter features a planar four‐membered silicon ring with a charge‐separated electronic situation. Two silicon atoms in 2 are trigonal planar and the other two trigonal pyramidal. In cycloadditions with ethylene, diethylacetylene, 1,5‐cyclooctadiene, and 2,3‐dimethyl‐1,3‐butadiene cyclic unsaturated ring compounds ( 3 – 6 ) were formed at room temperature in quantitative reactions. Two of the products ( 3 and 6 ) show photochemical isomerization with LED light (λ=405 nm) to afford saturated ring compounds 4 e and 6′ .