Abstract
In first chapter describes the copper-catalyzed [2+2]-cycloaddition of hydroxylamines with terminal alkynes in oxygen atmosphere to form corresponding β-lactams derivatives. β-lactam functionality commonly found in many natural products as well as biologically active molecules. The utility of this [2+2]-cycloaddition is manifested by wide scope of hydroxylamines and terminal alkynes. The second chapter describes one-pot copper-catalyzed [3+2]-cycloaddition of hydroxylamine with allene ether in oxygen atmosphere to form isoxazolidine derivatives. The use hydroxylamines provides a more convenient method to access isoxazolidine derivatives through insitu generated nitrone.