Synthetic approaches to phorbols via the intramolecular Diels–Alder reactions of furans (IMDAF): oxygen bridge cleavage and high stereocontrol during cycloaddition using α′-benzylthio substituted furan substrates
Abstract
High pressure mediated IMDAF of the α′-benzylthiofuran substrate 1 results in efficient and highly stereoselective cycloaddition; subsequent epimerisation of the cycloadduct 6 is regiospecific and the oxygen bridge may be opened by elimination or hydrolysis.