D. A. Evans Intramolecular methyl transfer: Speculation on the transition structures Chem 206 (CH3)N 16% intramolecular: 84% intermolecular exclusively intermolecular 9-membered cyclic transition state 8-membered cyclic transition state est C-o bond est c-o bond length 2.1 A length 2.1 A est C-n bond length 2.1 A est c-n bond length 2.1 A Approximate representation of the transition states of the intramolecular alkylation reactions. Transition state C-O and C-N bond lengths were estimated to be 1.5x(C-X)bond length of 1.4 A16% intramolecular; 84% intermolecular – + exclusively intermolecular + – D. A. Evans Intramolecular methyl transfer: Speculation on the transition structures Chem 206 est C–N bond length 2.1 Å est C–O bond length 2.1 Å 174° est C–O bond length 2.1 Å est C–N bond length 2.1 Å 174° Approximate representation of the transition states of the intramolecular alkylation reactions. Transition state C–O and C–N bond lengths were estimated to be 1.5x(C–X) bond length of 1.4 Å (CH3 )2N SO3CH3 SO3 (CH3 )3N SO3CH3 N(CH3 )2 N(CH3 )3 SO3 9- membered cyclic transition state 8- membered cyclic transition state