Diastereoselective synthesis of 6-functionalized 4-aryl-1,3-oxazinan-2-ones and their application in the synthesis of 3-aryl-1,3-aminoalcohols and 6-arylpiperidine-2,4-diones

Abstract Halocyclocarbamation of benzyl N -(1-phenyl-3-butenyl)carbamates afforded 6-functionalized 4-aryl-1,3-oxazinan-2-ones with moderate to excellent diastereoselectivity depending on the N -substituent. Importantly, in contrast to reported cyclocarbamations of homoallylic carbamates, which are generally trans -diastereoselective, cyclization of N -unsubstituted Cbz-protected homoallylamines led to cis -1,3-oxazinan-2-ones, predominantly. The use of N -benzylated and in situ prepared N -silylated derivatives resulted however in trans -selectivity. Transition states are proposed to explain the stereochemical influence of the N -substituent on the cyclocarbamations. The functionalized 1,3…