The stereochemistry of freelingyne and the synthesis of dihydrofreelingyne

Abstract

An unambiguous synthesis of the phenyl analogue of freelingyne from the Wittig reaction of a C₅ butenolide phosphorane with (E)-2-methyl-5-phenylpent-2-en-4-yn-l-a1 has confirmed that freelingyne is (2Z,4Z,6E)-9-(3'-furyl)-2,6-dimethylnona-2,4,6-trien-8-yn-4-olide (1). A similar stereo-selective synthesis has shown that the naturally occurring dihydrofreelingyne is (2Z,4Z,6E,8E)- 9-(3'-furyl)-2,6-dimethylnona-2,4,6,8-tetraen-4-olide (2).