First Total Synthesis of Paracaseolide A

The first total synthesis of the paracaseolide A, a very unusual tetraquinane oxa-cage bislactone recently isolated from the mangrove Sonneratia paracaseolaris, has been achieved. The final step and culmination of the eight-step synthetic sequence is a [4 + 2] dimerization of a 4-hydroxybutenolide, generated by singlet oxygen-mediated oxidation of a furan precursor.This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organic Letters, copyright American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see: http://pubs.acs.org/page/policy/articlesonrequest/index.htm