[3-BROMO-2-LITHIO-1-PHENYLSULFONYLBENZOFURAN.DIISOPROPYL ETHER]2 AND 3-FLUORO-2-LITHIO-1-PHENYL-SULFONYLBENZENE.PENTAMETHYLDIETHYLENETRIAMINE - CRYSTAL-STRUCTURES OF COMPOUNDS WITH LITHIUM AND HALOGEN ON NEIGHBORING CARBON-ATOMS

The crystal structures and reactivities in solution correlate for the title compounds. The β‐elimination of lithium and halide to the corresponding (hetero)aryne does not occur in the case of bromobenzofuran 1, in which the CBr bond length is that same as in its nonlithiated counterpart; LiF elimination does occur in compound 2, whose CF bond is lengthened in comparison to the neutral fluoroarene. This implies that the elimination is structurally predetermined. PMDETA = N, N, N′, N″, N″‐pentamethyldiethylenetriamine. (Figure Presented.) Copyright © 1991 by VCH Verlagsgesellschaft mbH, Germany