Solid-phase synthesis of beta-sultams

Solid-phase synthesis of beta-sultams amenable for construction of sulfonyl beta-lactam analogue combinatorial libraries is reported. Imine intermediates generated from polymer-immobilized amino acids and aldehydes are reacted with (chlorosulfonyl)acetates in the presence of pyridine to afford the solid-phase-tethered beta-sultam products. The latter can be released from support by acidic cleavage (TFA) or photocleavage, depending on the nature of the linker employed (acid-labile or photolabile linkers). Immobilized 4-(9-fluorenyl)methoxycarbonyl beta-sultams are further functionalized on supports to afford, upon cleavage, the respective carboxy and amido thiazetidine derivatives. The method can be employed in production of beta-sultam libraries for identification of new antibacterial agents.