An improved chemical synthesis of N-2 ((2S)-2-(3, 5-difluorophenyl)-2-hydroxyethanoyl)-N1- ((7S)-5-methyl-6-oxo-6, 7-dihydro-5H-dibenzo [b, d] azepin-7-yl)-l-alaninamide (LY411, 575, 9a), a known γ-secretase inhibitor, is described. The key synthetic steps, which used no chiral chromatography in the entire sequence, involved (1) improved microwave-assisted synthesis of a seven-membered lactam (±)-(5, 7-dihydro-6H-dibenz-[b, d] azepin-6-one 2, ...