Quinolinium tribromide; a mild and very efficient oxidant in organic synthesis

Abstract

Quinolinium tribromide has been used for the symmetric oxidation of anilines and thiols to the corresponding hydrazines and disulfides, respectively. This oxidant shows an excellent reactivity and selectivity in mild reaction conditions.

Disulfuration of Azlactones: A Versatile Entry to Unnatural, Disulfide-Linked Amino Acids and Peptides

“…[10,11] Despite the evident demand and promising potential of disulfide-functionalized amino acids and peptides, [2,3,12] those disulfurated specifically at the α-position constitute a unique yet rather underexplored chemical space. [13][14][15] The majority of known structures of this category belong to a wide-ranging family of natural products containing the venerable dithiodiketopiperazine ). [14,15] Although the construction of this nucleus can be achieved intramolecularly by several techniques, including thiol oxidation (Figure 1C(a)) [13,14] and nucleophilic disulfuration of iminium cation (Figure 1C(b)), [15] translating these intramolecular processes to generate acyclic, unsymmetrical αdisulfurated amino acids and peptides is nontrivial (Figure 1(c)).…”

“…[13][14][15] The majority of known structures of this category belong to a wide-ranging family of natural products containing the venerable dithiodiketopiperazine ). [14,15] Although the construction of this nucleus can be achieved intramolecularly by several techniques, including thiol oxidation (Figure 1C(a)) [13,14] and nucleophilic disulfuration of iminium cation (Figure 1C(b)), [15] translating these intramolecular processes to generate acyclic, unsymmetrical αdisulfurated amino acids and peptides is nontrivial (Figure 1(c)). In this respect, the α-disulfuration of amino acids and peptides with a disulfide electrophile via enolate intermediates is theoretically appealing yet practically challenging.…”