α-Alkylation of N-C Axially Chiral Quinazolinone Derivatives Bearing Various ortho -Substituted Phenyl Groups: Relation between Diastereoselectivity and the ortho -Substituent

2-Ethylquinazolin-4-one derivatives bearing various ortho -substituted phenyl groups were revealed to possess a stable C-N axially chiral structure at ambient temperature. The reactions of alkyl halides with the anionic species prepared from these quinazolinones were systematically explored. The α-alkylation reactions proceeded with diastereoselectivities ranging from 1:1 to >50:1, depending upon the steric bulk of the ortho -substituent, to afford products having the elements of axial and central chirality in high yields (85-98%).