Synthesis of cGAMP surrogate used as STING agonist and mechanistic study of intermolecular Rauhut-Currier reaction of $\alpha^{'}, \gamma-dioxycyclohexenone$

Abstract

The reduction of tertiary amides in the presence of secondary amides was investigated by thiolation of the tertiary amides followed by reduction to afford ethylphenyl-substituted peptide macrocyclic ring. We were able to access the same macrocyclic ring through amide bond coupling to generate the adenine-substituted reduced-cyclic peptide nucleic acid. Also, the mechanistic study of an intermolecular Rauhut-Currier reaction was performed with various $\alpha^{'}, \gamma-dioxycyclohexenones$. The general principle guiding the formation of [3+2] adducts and RC products was investigated. Several factors such as the hydrogen bonding and the configuration of the [3+2] intermediates were examined.