REACTIONS OF (Me3Si)3CSiMe2R COMPOUNDS (R = CH=CH2, CH2CH=CH2, CCPh, Ph, AND CH2Ph) WITH ELECTROPHILES

Article abstract of DOI:10.1016/0022-328X(85)80199-6

No products of addition to the multiple bond are formed in reactions of TsiSiMe2R species (Tsi=(Me3Si)3C; R=CH=CH2, CH2CH=CH2, or (CCPh) with halogens or hydrogen halides.TsiSiMe2CH=CH2 gave (a) TsiSiMe2Cl on treatment with ICl in CCl4; (b) TsiSiMe2Br on treatment with Br2 in CCl4;.(c) TsiSiMe2I (slowly) on treatment with I2 in CCl4; and (d) TsiSiMe2OCOCF3 on treatment with neat CF3CO2H.TsiSiMe2CH2CH=CH2 gave: (a) TsiSiMe2Cl and TsiSiMe2I on treatment with ICl in CCl4; (b) TsiSiMe2Br on treatment with Br2 in CCl4; (c) TsiSiMe2I on treatment with I2 in CCl4; and (d) TsiSiMe2OCOCF3 rapidly on treatment with neat CF3CO2H.TsiSiMe2Ph gave TsiSiMe2Br on treatment with Br2 in CCl4 or CH3CO2H, and (b) TsiSiMe2Cl on treatment with HCl in Et2O.Reaction of TsiSiMe2Ph with nitric acid in (CH3CO)2O gave two mono-nitration products, probably the m- and p-isomers.Reaction of TsiSiMe2CH2Ph with Br2 gave exclusively TsiSiMe2Br, whereas reaction with nitric acid in (CH3CO)2O gave o- and p-nitro derivatives in 65/35 ratio.This last result casts serious doubt on previously proposed explanations of the predominance of ortho-nitration in the case of Me3SiCH2Ph.