Premium
2‐Boraindane und 2‐(Dialkylamino)1‐2‐benzoborol‐Dianionen
Author(s) -
Herberich Gerhard E.,
Eigendorf Uwe,
Englert Ulli
Publication year - 1993
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19931260618
Subject(s) - chemistry , adduct , stereochemistry , ring (chemistry) , derivative (finance) , medicinal chemistry , organic chemistry , economics , financial economics
2‐Boraindanes and 2‐(Dialkylamino)1‐2‐benzoborole Dianions ortho 1‐Xylene reacts with the Lochmann‐Schlosser base to produce a mixture of the potassium derivatives K 2 [1,2‐C 6 H 4 (CH 2 ) 2 ] ( 2 ) and K[2‐MeC 6 H 4 CH 2 ] ( 3 ). Condensation of 1 + 2 with BCl 2 (NR 2 ) (RMe, Et, i Pr) affords 2‐(dialkylamino)1‐2‐boraindanes ( 1a–c ) (50%). Treatment of 1a, b with LiTMP/TMEDA in THF yields dilithio derivatives [Li(tmeda)] 2 [C 6 H 4 (CH) 2 BNR 2 ] ( 8a, b ) (40%) which show tripledecked structures consisting of an aromatic 10′‐electron 2‐benzoborole dianion and two [Li‐(tmeda)] + units facially bound to the borole ring. 1a reacts with HCl/Et 2 O/hexane to give C 6 H 4 (CH 2 ) 2 BCl · OEt 2 ( 1d · OEt 2 ) (76%) which decomposes in vacuo to give the chloro derivative 1d . The methyl derivative C 6 H 4 (CH 2 ) 2 BMe ( 1e ) is obtained from 1a by treatment with LiMe/Et 2 O at –78°C and subsequently with HCl/Et 2 O at –78°C (41%). 1a, b react with MeOH at –78°C to give solid adducts C 6 H 4 (CH 2 ) 2 BOMe · NHR 2 ( 12a, b ) while 1c affords C 6 H 4 (CH 2 ) 2 BOMe ( 1f ). Subsequent ring‐opening produces 2‐MeC 6 H 4 CH 2 B(OMe) 2 ( 13 ). With the exception of 1b the 2‐boraindanes 1 are crystalline solids. The silylation of the 2‐benzoborole dianions and various (2‐methylbenzyl)borane derivatives is also described.