| Popis: |
Double kaliation of 1-isopropenyl-2-methylbenzene ( 4 ) and subsequent ring closure with BCl 2 (NR 2 ) (R=Me, i Pr) provides a new and efficient access to 1,2-dihydro-2-boranaphthalenes 6′ and, after metalation with LDA in Et 2 O or with LiN(SiMe 3 ) 2 in hexane, to lithium 2-boratanaphthalenes 7 . The substituent at boron may be modified. Treatment of the B -dialkylamino compounds with BCl 3 affords the highly reactive β -chloro derivative 6c′ , and subsequent methylation with ZnMe 2 in toluene affords the B -methyl compound 6d′ . The lithium 2-boratanaphthalenes 7 readily form transition metal complexes such as Cp * Fe(4-MeC 9 H 6 BNMe 2 ) ( 9 ) and Cp * ZrCl 2 (4-MeC 9 H 6 BMe) ( 10 ) with hexahapto coordination of the metal to the boron-containing ring. |
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