A 4-Step Symmetric Synthesis of MonomorineWashington University in St. Louis (2016)
I present progress made during the Fall 2016 semester toward synthesizing monomorine (3R,5S,8aS)-3-Butyl-5-methyloctahydroindolizine), a trail pheromone of the pharaoh ant based on the simple synthesis from 2,6-lutidine described by Oliver and Sonnet in 1974. This synthesis is attractive due to its simplicity, however there are few experimental details in the original paper, which also does not present data that the synthesis was successful. Synthesis following the Oliver and Sonnet scheme was largely unsuccessful due to difficulties with the prescribed Ph3P•Br2 cyclization step. An alternative cyclization scheme using mesylation of the alcohol produced significant quantities of the desired dihydroindolizinium ion, however we encountered difficulty with the hydrogenation, producing only a small quantity of monomorine. We conclude that further investigation of the Oliver and Sonnet synthesis is necessary to develop the mesylation step to be synthetically viable and to determine the source of the difficulties with the Ph3P•Br2 cyclization. This alternative cyclization scheme also has the potential to produce an enantioselective synthesis of monomorine if a single enantiomer of 1,2-epoxyhexane can be developed.
Publication DateFall December 16, 2016
LocationSt. Louis, MO
Citation InformationThomas Van Horn and Vladimir B Birman. "A 4-Step Symmetric Synthesis of Monomorine" Washington University in St. Louis (2016)
Available at: http://works.bepress.com/thomas_vanhorn/4/