yield is only 16%. 2b Schmid and Wolkoffz" have reported the selective obtention of 2b by the rearrangement at 400-425" C of the vinylcyclopropane derivative 4b, secured from diethyl malonate and trans-1, 4-dichloro-2-butene, and the conversion of 2b as before to acid 3 (32% overall yield). Alternatively, 3 has been prepared from cyclopentadiene in five steps in 19% overall yield.'j Recently, we required large amounts of acid 3 for work on a ...
