Synthesis of Fluorinated Analogues of Geraniol

Article abstract of DOI:10.1021/jo00321a003

Syntheses of 3-(fluoromethyl)geraniol (4), 3-(difluoromethyl)geraniol (14), and 3-(trifluoromethyl)geraniol (20) are described.The key reaction in the routes to alcohols 4 and 20 which establishes the geranyl Z stereochemistry at the C(2)-C(3) double bond is the cis addition of (4-methylpent-3-en-1-yl)copper reagents to derivatives of ethyl 2-butynoate bearing appropriate functional groups at C(4).Attempts to prepare difluoromethyl alcohol 14 by similar routes were unsuccessful.However, the carbon skeleton of 14 was constructed by a Wittig condensation of 1,1-difluoro-6-methylhept-5-en-2-one (12) with triethyl phosphonoacetate in a reaction that yielded a 72:28 ratio of geranyl/neryl isomers.