Asymmetric synthesis of pentono- and 6-deoxyhexono-δ-lactams via hetero-Diels-Alder reactions with nitroso dienophile

Asymmetric Diels‐Alder reaction of the pentadienoic and hexadienoic acids 2a,b with the chiral chloronitroso derivative 3 gave the primary adducts 4a,b with good‐to‐excellent enantioselectivity. Subsequent as‐ or trans‐dihydroxylation and hydrogenolytic cleavage of the NO bond led to the 5‐amino‐5‐deoxypentono‐δ‐lactams 13a, 14, 15a, and 16 in the D‐ribose, L‐arabinose, D‐xylose, and L‐lyxose series, respectively, and to the 5‐amino‐5,6‐dideoxyhexono‐δ‐lactams 13b and 15b in the D‐allose and D‐glucose series, respectively.