Bicyclic 5-6 Systems with One Ring Junction Nitrogen Atom: Two Extra Heteroatoms 1:1

Synthesis of heteroaryl substituted α‐amino acid derivatives, polyols, and related compounds

“…This activation can be achieved by transformation into another functional group which is a better building block for the formation of a heterocyclic ring. Such versatile and useful building blocks in heterocyclic chemistry are α-halo ketones and aldehydes since they enable the formation of various heterocyclic systems such as thiazoles [9], indolizines [10], imidazo[1,2-x]azines [11,12], and 1,2,4-triazolo [4,3-x]azines [13,14]. Transformations of (S)-aspartic acid (1) into (S)-3-formylalanine-and (S)-5-bromo-4-oxonorvaline derivatives have been described previously [15][16][17][18][19].…”