Complex sentence: Corey described a total synthesis of the compound "dihydrocostunolide" and although in it an electrocyclic reaction is described Corey has nothing to offer with respect to explaining its stereospecifity.
Split into simpler sentences: Corey described a total synthesis of the compound "dihydrocostunolide". Although in it an electrocyclic reaction is described, Corey has nothing to offer with respect to explaining its stereospecifity.