Sometimes an organometallic complex can act as the intermediate in the synthesis of orga...

Sometimes an organometallic complex can act as the intermediate in the synthesis of organic compounds. The heterocyclic compound (TBS) shown below was reacted with LiBH(C₂H₅)₃ to form X , a halogen-free heterocycle. When X was treated with Cr(CO)₃(CH₃CN)₃, followed by reaction with HF·pyridine, transition-metal complex Y , which had strong absorptions at 1898 and 1975 cm^-1, formed. Addition of triphenylphosphine gave a new transition- metal complex plus heterocycle Z . The 1H NMR spectrum of Z showed four single peaks of equal intensity between d 6.4 and 7.8 ppm, a quartet at 4.9 ppm, and a triplet at 8.44 ppm. Propose structures for X , Y , and Z . (See A. J. V. Marwitz, M. H. Matus, L. N. Zakharov, D. A. Dixon, S-H. Liu, Angew. Chem., Int. Ed ., 2009 , 48 , 973.)