A Highly Stereoselective Synthesis of Chiral α-Amino-β-lactams via the Kinugasa Reaction Employing Ynamides
摘要:
A highly stereoselective synthesis of chiral alpha-amino-beta-lactam through an ynamide-Kinugasa reaction is described. In addition, a mechanistic model is illustrated here to rationalize the observed diastereoselectivity, which depends on both the initial [3 + 2] cycloaddition step and the subsequent protonation for which both are highly selective.
Highly Substituted 2-Amido-furans From Rh(II)-Catalyzed Cyclopropenations of Ynamides
摘要:
Rh(II)-catalyzed cyclopropenations of ynamides are described. Although an actual amido-cyclopropene intermediate may not be involved, these reactions provide a facile entry to highly substituted 2-amido-turans, thereby formerly constituting a [3 + 2] cycloaddition. An application of these de novo 2-amido-turans in N-tethered intramolecular [4 + 2] cycloadditions is also illustrated, leading to dihydroindoles and tetrahydroquinolines.