A Synthetic Study of Biologically Active Compounds using Intramolecular Amidation

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Electrophilic olefin cyclization leading to carbon-heteroatom bonding is a very important process, particularly in the regio- and stereo- selective synthesis of heterocycles leading to biologically active compounds. We found an attractive iodine-induced lactamization on gamma,delta-and gamma,epsilon unsaturated thioimidates. Iodine-induced lactamization from gamma-unsturated thioimidates proceeds diastereo, regio(5-exo-trig)-, and stereo-selectively (1,2-cis- and 1,3-trans asymmetric induction), providing highly functionalized gamma-lactams, which are convertible into related biologically active compounds.Next, we found a intramolecular amidomercuration of N-delta, epsilon-unsaturated -gamma-hydroxyurethanes, giving cis-2-3-hydroxyuretnane. Interestingly, the Sharpless kinetic resolution of N-delta,epsilon-unsaturated-gamma-hydroxyalkenyl- urethanes provided optically active allylic alcohols and cis-3-hydroxy- 2-(hydroxymethyl)pyrrolidines. They were transformed into key synthetic intermediates for several biologically active compounds.