Reactions of the neohexyl iodide complex [(.eta.5-C5H5)Re(NO)(PPh3)(ICH2CH2C(CH3)3)]+BF4- and nucleophiles: stereochemistry of carbon-iodine bond cleavage in highly accelerated SN2 reactions Academic Article uri icon

abstract

  • Reaction of (η5−C6H5)Re(NO)(PPh3)(CH3)) ICH2CH2C(CH3)3 (2), and HBF4•OEt2 in C6H5Cl gives neohexyl iodide complex [(η5−C6H5)Re(NO)(PPh3)(ICH2CH2C(CH3)3)]+BF4− (3, 81%). Complex 3 and PPh3 react (−40 °C, CD2C12) to give [Ph3PCH2CH2C(CH3)3]+BF4− (7) and (η5−C5H5)Re(NO)(PPh3)(I) (6) in >99% spectroscopic yields. Complex 3 and [Ph3P-N-PPh3]+Br- (PPN+Br−) react (−40 °C, CD2C12) to give BrCH2CH2C(CH3)3 (8) and 6 in 97-99% spectroscopic yields. Deuterated neohexyl halides erythro-ICHDCHDC(CH3)3 (erythro-2-d2), threo-2-d2, erythro-8-d2, and threo-8)-d2 are prepared via (η5− C5H5)2Zr(Cl)(X) compounds. The labeled complexes erythro-3-d2 and threo-3-d2 are synthesized, and analogous reactions with PPN+Br− and PPh3 are conducted. Diastereomer ratios of the products 8−d2 and 7−d2, and all preceding deuterated compounds, are analyzed by 500-MHz 1H{2H} NMR spectroscopy. In all cases, the carbon-iodine bond in 3−d2 is cleaved with essentially complete inversion of configuration at carbon. © 1991, American Chemical Society. All rights reserved.

author list (cited authors)

  • Igau, A., & Gladysz, J. A.

citation count

  • 16

publication date

  • July 1991