Highly Enhanced Enantioselectivity in the Memory of Chirality via Acyliminium Ions^†

Electrochemical oxidation of N-acylated serine derivative 1b in methanol gave optically active methoxylated compound 2b with an enantiomeric excess of up to 80%. The bulky o-phenyl benzoyl N-protecting group was found to be the main contributing factor for the enhanced enantioselectivity. The mechanistic aspect of this methoxylation reaction was investigated and found to proceed via a retention mechanism.