Walker, Johannes C. L.Johannes C. L.WalkerOestreich, MartinMartinOestreich2020-05-132020-05-132019https://resolver.sub.uni-goettingen.de/purl?gro-2/65262The design and gram-scale synthesis of a cyclohexa-1,4-diene-based surrogate of isobutene gas is reported. Using the highly electron-deficient Lewis acid B(C6 F5 )3 , application of this surrogate in the hydromethallylation of electron-rich styrene derivatives provided sterically congested quaternary carbon centers. The reaction proceeds by C(sp3 )-C(sp3 ) bond formation at a tertiary carbenium ion that is generated by alkene protonation. The possibility of two concurrent mechanisms is proposed on the basis of mechanistic experiments using a deuterated surrogate.enjournal_article10.1002/anie.20190985231449730