Halogen derivatives of monocarbon carboranes, nido-7-Me3N-7-CB10H12, closo-2-Me3N-2-CB10H10 and closo-1-Me3N-1-CB11H11

摘要

Electrophilic iodination and bromination (X-2-AlCl3) of nido-7-Me3N-7-CB10H12 gave nido-4-I-7-Me3N-7-CB10H11 and nido-4,6-I-2-7-Me3N-7-CB10H10 and the bromine-substituted analogaes nido-4-Br-7-Me3N-7-CB10H11 and nido-4,6-Br-2-7-Me3N-7-CB10H10. Electrophilically induced nucleophilic substitution (HI-AlCl3) gave nido-9-I-7Me(3)N-7-CB10H10. These compounds readily deprotonated to the dianions [nido-7-Me3N-7-CB10H10](2-), [nido-4-I-7-Me3N-7-CB10H9](2-) and [nido-4,6-I-2-7-Me3N-7-CB10H8](2-), and oxidation (chemical or electrochemical) gave derivatives of closo-2-Me3N-2-CB10H10 and closo-3-I-2-Me3N-2-CB10H9. Low temperature insertion reactions of the anions with PhBCl2 gave closo-8-I-2-Ph-1-Me3N-I-CB11H9 and closo-8-Br-2-Ph-1-Me3N-I-CB11H9, while electrophilic iodination occurred at B(12) to give closo-12-I-1-Me3N-I-CB11H9. Palladium catalysed substitution of iodine resulted in the nido and close derivatives closo-8-CH2=CHCH2-2-Ph-1-Me3N-1-CB11H9 and nido-4CH(2)=CHCH2-7-Me3N-7-CB10H11. AMI Calculations were used to help rationalise a mechanism for the boron insertion reactions. [References: 12]