Acid Cyclization and Other Products of the Germacranolide Epoxide Lipiferolide

Article abstract of DOI:10.1021/jo00171a019

A comparison was made of the products generated from lipiferolide (2) upon treatment with SOCl2, HCl, and BF3*Et2O.SOCl2 formed three epoxide-opened compounds, chlorhydrin 3 and two allylic alcohols, 4 and 5, three cyclization products of the guaianolide type, chloro compound 9 and olefins 1 and 10, as well as three novel bicyclo<6.2.0>decanes, 6, 7, and 8.HCl generated the epoxide-opened substances 3, 4, and 5 and guaianolides 1, 9, and 10, but no cyclobutane products.BF3*Et2O gave fluorohydrin 11 as the major component and ketone 12, xanthanolide 13, and epitulipinolide (4,5-deoxylipiferolide) as compounds not observed from the other reagents, along with small yields of allylic alcohol 4 and guaianolides 1 and 10.