%A Joseph Lizza
%T DEVELOPMENT OF THE 2,2,6,6-TETRAMETHYLPIPERIDIN-1-YLOXYCARBONYL (TEMPOC) PROTECTING GROUP AND EFFORTS TOWARDS THE TOTAL SYNTHESIS OF ?-CYCLOPIAZONIC ACID
%X The 2,2,6,6-Tetramethylpiperidin-1-yloxycarbonyl (Tempoc) protecting group is a new carbamate protecting group for various types of amines. Installation can be accomplished using the new reagent 4-nitrophenyl (2,2,6,6-tetramethylpiperidin-1-yl) carbonate (NPTC) under mild conditions. Tempoc is stable under strongly acidic and basic conditions, and displays orthogonal deprotection properties when used in tandem with the tert-butyloxycarbonyl (Boc) and benzyloxycarbony (Cbz) protective groups. Deprotection can be accomplished under thermolytic conditions at 135 ?C, or under reductive conditions with in situ generated catalytic Cu(I). Furthermore, Tempoc has also been shown to be a useful protecting group in peptide synthesis. Protecting a broad range of biologically relevant amino esters has been accomplished in the presence of 1-hydroxybenzotriazole (HOBt) as an NPTC activator. Demonstration of Tempoc utility has been realized through the synthesis of a tripeptide fragment of Gramicidin S, a cyclic decapeptide that possesses antimicrobial activity. Unrelated, efforts toward the total synthesis of ?-Cyclopiazonic acid are also discussed. The ambitious 1,3-dipolar cycloaddition of a highly substituted aziridine with relatively unactivated dipolarophiles led to interesting results that may be useful for the synthesis of other complex biologicals and natural products.
%D 2020
%K peptides, cycloaddition, natural products
%I University of Pittsburgh
%L pittir38135