Abstract
A remarkable solvent preference for dehydrobromination to yield 10-Undecynoic acid (5) and 9-Undecynoic acid (6) is observed in the case of 10,11-dibromoundecanoic acid (1). Thus, 10-Undecenoic acid can be easily and quantitatively converted to 6 in PEG-400, while 5 is produced in PEG-200. 5 can also be obtained in non-polar solvents with PEG-200/400 as a phase transfer catalyst.