Thermal decomposition of methyl aryl cyclopropylcarbinyl borates, followed by hydrolysis, gives rise to mixtures of 1-aryl-1-cyclopropylethylene, and of 4-aryl-3-pentenol. Similarly, aryl cyclopropylcarbinylborates yield trans-4-aryl-3-butenols, while dicyclopropyl carbinyl borate gives a mixture of trans- and cis-4-cyclopropyl-3-butenols. © 1968.