Sulfur-Switch Ugi Reaction for Macrocyclic Disulfide-Bridged Peptidomimetics.

A general strategy is introduced for the efficient synthetic access of disulfide linked artificial macrocycles via a Ugi four-component reaction (U4CR) followed by oxidative cyclization. The double-mercapto input is proposed for use in the Ugi reaction, thereby yielding all six topologically possible combinations. The protocol is convergent and short and enables the production of novel disulfide peptidomimetics in a highly general fashion.