While six-membered chelates have been reported to form and lead to anti-products in additions to β-alkoxy aldehydes, conformational preferences of the chelate are not typically discussed. In a conformationally related reaction, Stevens uses stereoelectronic arguments to rationalize the highly selective reactions of vinyl alcohols and tetrahydropyridinium ions that adopt half-chair conformers resembling 6a and 6b (Figure , C). Anti-7 ultimately arises from nucleophilic attack on conformer 6b from a mode of attack that avoids formation of twist-boat products or build up of 1,3 diaxial strain. Taking this model into consideration, should a six-membered chelate form in Lewis acid mediated additions to β-alkoxy N-Ts imines, stereoelectronic arguments similar to Stevens' rationale and Fürst-Plattner rules may be applied to predict and control for stereochemical outcomes of half-chair six-membered chelates.