3,4- and 3,5-Disubstituted 2-Pyridones Using an Intermolecular Cycloaddition / Cycloreversion Strategy: Toward the
Maren K Leibowitz1, Ethan S Winter1, Jonathan R Scheerer1
1Department of Chemistry, The College of William & Mary, P. O. Box 8795, Williamsburg, VA 23187, USA.
Abstract:
The intermolecular cycloaddition of pyrazinone precursors with alkyne substrates was evaluated. The resulting regioisomeric [2.2.2]-diketopiperazine alkene cycloadducts were diverted into 2-pyridone products through cycloreversion of the [2.2.2]-bicyclic intermediates. New insights into the regioselectivity of pyrazinone azadiene Diels-Alder reactions as well as cycloreversion reactivity were revealed in this study. Synthetic sequences using this [4+2]/r[4+2] strategy were determined that can produce predominantly the 3,5-disubstituted 2-pyridone alkaloid structures; pyridones featuring the 3,4-substitution pattern are observed as the minor regioisomeric products.
Related Concept Videos
Cycloaddition Reactions: Overview
Cycloaddition Reactions: MO Requirements for Thermal Activation
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Thermal and Photochemical Electrocyclic Reactions: Overview
Cycloaddition Reactions: MO Requirements for Photochemical Activation


![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)