Stereoselective Peterson Olefinations from Bench-Stable Reagents and N-Phenyl Imines

The synthesis of bench‐stable α,α‐bis(trimethylsilyl)toluenes and tris(trimethylsilyl)methane is described and their use in stereoselective Peterson olefinations has been achieved with a wide substrate scope. Product stereoselectivity was poor with carbonyl electrophiles (E/Z ∼1:1 to 4:1) though this was significantly improved by employing the corresponding substituted N‐benzylideneaniline (up to 99:1) as an alternative electrophile. The olefination byproduct was identified as N,N‐bis(trimethylsilyl)aniline and could be easily separated from product by aqueous acid extraction. Evidence for an autocatalytic cycle has been obtained. A mild method for E‐selective Peterson olefinations is described. Bench‐stable α,α‐bis(trimethylsilyl)toluenes and tris(trimethylsilyl)methane are used as reagents in reaction with substituted N‐phenyl imines (see scheme).