Fluorous synthesis of a tri-beta-peptide library and eight stereoisomers of macrolactone Sch725674

Chapter 1 of this dissertation describes a new strategy to make β-peptide libraries. A 27-membered tri-β-peptide library was prepared. β-Azido acids as building blocks were tagged with fluorous PMB group. Two reduction-amide coupling cycles were done. Intermediates were separated by Fluorous Solid Phase Extraction (FSPE). The reductive deprotection gave the final 27 tri-β-peptide, which were purified by reverse phase HPLC. Purity of the library was checked by LC-MS. Mass spectroscopy data of 25 products matched with calculation.;Chapter 2 describes the Fluorous Mixture Synthesis (FMS) of eight stereoisomers of 14-membered macrolactone Sch725674. The configurations of Sch725674 were completely unknown when discovered. A single diastereomer of Sch725674 was prepared first by traditional solution phase synthesis. In the FMS, stereoisomeric starting materials were tagged with different fluorous TIPS groups. The tagged quasidiastereomers were mixed and the mixture underwent a series of steps to make the fluorous tagged macrolactones, which were separated by fluorous HPLC followed by individual deprotections to provide the eight final products. The NMR data of the eight synthetic macrolactones were compared with those of Sch725674. The absolute configuration of Sch725674 was confirmed as (4 R,5S,7R,13R).