Syntheses of Chroman-2-ones and α-Amino Acids through a Diastereoselective Domino Reaction

摘要: Many 3-aminochroman-2-ones and β,β-diarylalanines exhibit significant biological activities. A new method was thus developed for the syntheses of these compounds with high efficiency diastereoselectivity. First, treatment various phenols Erlenmeyer–Plochl (Z)-azlactones AlCl3 in toluene produced desired cis-3-aminochroman-2-ones 65–90% yields under kinetic control. This coupling reaction involved a domino process Friedel–Crafts alkylation, 1,4-AlCl3 shift, transesterification, protodealumination “single-flask.” The corresponding products, however, were not generated by replacement protonic acid. Second, hydrolysis resultant 3-amino-4-arylchroman-2-ones NaHCO3 mixture THF water gave α-(N-benzoyl)amino acids. Further deprotection isolated use hydrochloric acid (12 N) methanol afforded free amino acids 80–88% yields. Under optimized conditions, epimerization did occur at α carbons...