The ‘Azirine/Oxazolone Method’ on Solid Phase: Introduction of Various α,α‐Disubstituted α‐Amino Acids

Peptides containing various α,α‐disubstituted α‐amino acids, such as α‐aminoisobutyric acid (Aib), 1‐aminocyclopentane‐1‐carboxylic acid, α‐methylphenylalanine, and 3‐amino‐3,4,5,6‐tetrahydro‐2H‐pyran‐3‐carboxylic acid have been synthesized from the N‐ to the C‐terminus by the ‘azirine/oxazolone method’ under solid‐phase conditions. In this convenient method for the synthesis of sterically demanding peptides on solid‐phase, 2H‐azirin‐3‐amines are used to introduce the α,α‐disubstituted α‐amino acids without the need for additional reagents. Furthermore, the synthesis of poly(Aib) sequences has been explored.