Borole derivatives XXI, 2,5-diphenyl-2,5,-dihydro-1H-boroles; strctures of tert-butyl-2,5,-diphenyl-2,5-dihydro-1H-borole and of bis(tmeda) lithium 2,5-diphenyl-2,5-dihydro-1H-borolediide
作者:Gerhard E. Herberich、Trixie Wagner、Hans-W. Marx
DOI:10.1016/0022-328x(95)05818-a
日期:1995.10
The magnesium reagent Mg(C(4)H(4)Ph(2))(THF)(3) derived from (E,E)-1,4-diphenyl-1,3-butadiene reacts with boron dihalides BCl2(NR(2)) (R=Me, Et,Pr-i) and (t)BuBF(2) to give 2,5-dihydro-2,5-diphenyl-1H-boroles 2,5-Ph(2)C(4)H(4)BNR(2) (la-lc) and 2,5-Ph(2)C(4)H(4)B(t)Bu (Id) as mixtures of cis-trans isomers. cis-ld possesses a classical structure with a ring folding of 8 degrees along the line C-2,C-5 of the C4B ring. The dimethylamino compounds la undergo metallation when treated with LDA in THF. After addition of TMEDA, the product can be crystallized from hexane-THF (2:1) as [Li(TMEDA)](2)[2,5-Ph(2)C(4)H(2)BNMe(2)] (3). The structure of 3 is that of a contact ion triple with a triple-decker-like arrangement of the borole ring and two [Li(TMEDA)](+) units.