Total synthesis of (-)-platensimycin by internal H-bond mediated intramolecular Diels-Alder reaction

Abstract

We have investigated 3,5-dibromo-2-pyrone as a new synthetic starting point toward target-oriented synthesis, utilizing its peculiar reactivity as a neutral diene and the selective maneuverability of the two bromine groups. Such efforts have resulted in the successful synthesis of a series of biologically valuable natural products. Inspired by our recent success on internal hydrogen-bond mediated asymmetric DielsAlder reaction of 2-pyrones, we have launched a program to invent a new route that would allow efficient asymmetric synthesis of (-)-platensimycin. The key transformations include the C3-selective Sonogashira coupling reaction of 3,5-dibromo-2-pyrone, SmI2-mediated stereoselective reduction, and asymmetric intramolecular Diels-Alder cycloaddition reaction. Recent progress toward total synthesis of (-)-platensimycin is presented in this thesis.