title: Transition Metal-Free Cascade Cyclization of Epoxy-Ynamides: To Go for 1,3-Oxazines or 1,4-Oxazines?
abstract: An approach to both 1,3- and 1,4-oxazines is developed by the cascade cyclization of epoxy ynamides under transition metal-free conditions. Thus, while 1,3-oxazines are obtained in a regio- and stereoselective manner by using base, cyclization of epoxy ynamides with sodium azide as a nucleophile results in 1,4-oxazines. Deuterium-labeling experiment demonstrates the role of water as a proton source in the formation of 1,4-oxazines. Epoxy tethered alkyne precursors provide 1,4-oxazines that undergo click reaction.
authors: School of Chemistry, University of Hyderabad , Hyderabad-500046, Telangana, India.
authors: A Leela
authors: AL
authors: Siva Kumari
authors: School of Chemistry, University of Hyderabad , Hyderabad-500046, Telangana, India.
authors: Alla
authors: A
authors: Siva Reddy
authors: School of Chemistry, University of Hyderabad , Hyderabad-500046, Telangana, India.
authors: K C Kumara
authors: KC
authors: Swamy