Inverse Electron-Demand [4 + 2]-Cycloadditions of Ynamides: Access to Novel Pyridine Scaffolds

Functionalized polycyclic aminopyridines
are central to the chemical
sciences, but their syntheses are still hampered by a number of shortcomings.
These nitrogenated heterocycles can be efficiently prepared by an
intramolecular inverse electron demand hetero Diels–Alder (ihDA) cycloaddition of ynamides to pyrimidines. This ihDA/rDA
sequence is general in scope and affords expedient access to novel
types of aminopyridinyl scaffolds that hold great promise in terms
of exit vector patterns.