Zur Reaktivität des Silaethens Me₂Si = C(SiMe₃)₂: Relative Geschwindigkeiten der Diels‐Alder‐Reaktionen mit organischen Dienen^1,2)

Abstract

On the Reactivity of the Silaethene Me 2 Si = C(SiMe 3 ) 2 : Relative Rates of Diels‐Alder Reactions with Organic Dienes 1,2) [4 + 2] Cycloaddition of dienes to silaethene Me 2 Si = C(SiMe 3 ) 2 is accelerated in the directions: (i) butadiene < isoprene < CH 2 = CR – CH = CH 2 with R = CH 2 SiMe 2 CH‐ (SiMe 3 ) 2 (increase in electron donation of the diene substiuents), (ii) trans ‐piperylene < 2,3‐dimethylbutadiene (DMB) < isoprene (decrease in steric hindrance of diene substituents), (iii) cis ‐piperylene or cis,trans ‐hexadiene < trans ‐piperylene and trans,trans ‐hexadiene (decrease in equilibrium concentration of the cisoid conformer).