In the present study, we conducted biopanning of T7 phage-displayed peptides either on a 96-well formatted microplate, a flow injection-type quartz-crystal microbalance (QCM) biosensor, or a cuvette-type QCM. Roxithromycin (RXM) is a semi-synthetic fourteen-membered macrolide antibiotic that shows anti-angiogenic activity in solid tumors. The transformations of the furan rings in the obtained products were also investigated. Furthermore, two reaction conditions, that is, the use of 1.4 equivalents of a boron trifluoride-diethyl ether complex or 0.4 and 0.2 equivalents of trimethylsilyl triflate and methoxytrimethylsilane, respectively, were established for the conversion of 2-acylfurans into the corresponding 1,3-cyclopentanediones in acceptable yields. To overcome this limitation of the method, we used 2-acylfuran derivatives as the reactants to synthesize 2,2-disubstituted-1,3-cyclopentanediones. However, the adoption of α-oxy-functionalized ketones/ketals is quite difficult, as demonstrated by our experiments. The reported method for the synthesis of these compounds involves the semi-pinacol rearrangement of a Mukaiyama-aldol adduct prepared from a ketone/ketal and 1,2-bis(trimethylsilyloxy)cyclobutene. 2,2-Disubstituted-1,3-cyclopentanediones are versatile building blocks for synthesizing complex natural products with bicyclic structures including cyclopentane rings.

S. suzuki manuscript letters