A reactivity study of [η6-(tert-butylsulfonyl)benzene]-tricarbonylchromium(0)

Abstract

Addition of nucleophiles [LiC(Me)₂CN, Li[graphic omitted], BrMgCH₂CHCH₂, LiCH₂CO₂Bu^t] to tricarbonyl[η⁶-(tert-butylsulfonyl)benzene]chromium(0) 4 followed by iodine oxidation gives moderate to excellent yields (43–97%) of the novel para-disubstituted arenes 5a–d. Treatment of complex 4 with 1.0 or 2.1 equiv. of butyllithium followed by an electrophilic quench (ClSiMe₃, ClCO₂Me, ClPPh₂, MeSSMe) gives the ortho- and di-ortho-substituted products 6a–b and 7a–d, respectively in moderate to excellent yield (40–90%). Addition of complex 4 to 1.0, 2.0 and 3.5 equiv. of LiTMP (LiTMP = lithium 2,2,6,6-tetramethylpiperidide) followed by a ClSiMe₃ quench gives the ortho silylated product 6a, the ortho, meta disilylated product 9 and, surprisingly, the ortho, ortho, para trisilylated product 10 respectively. The structure of [η⁶-1-(tert-butylsulfonyl)-2,5-bis(trimethylsilyl)benzene]tricarbonylchromium(0) 9 has been established by an X-ray crystallographic analysis.