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3,4‐Dimethylenborolane und 3,7‐Diborabicyclo[3.3.0]oct‐1(5)‐ene
Author(s) -
Herberich Gerhard E.,
Eigendorf Uwe,
Englert Ulli
Publication year - 1994
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.19941270611
Subject(s) - chemistry , adduct , crystal structure , ene reaction , magnesium , yield (engineering) , molecule , derivative (finance) , stereochemistry , crystallography , x ray crystallography , medicinal chemistry , diffraction , organic chemistry , materials science , physics , optics , economics , financial economics , metallurgy
3,4‐Dimethyleneborolanes and 3,7‐Diborabicyclo[3.3.0]oct‐1(5)‐enes The tetramethyleneethane derivative K 2 [C 2 (CH 2 ) 4 ] which is readily prepared from 2,3‐dimethylbutadiene by metallation with the Lochmann‐Schlosser base reacts with BC1 2 (NR 2 ) (RMe, Et, i Pr) to give the highly reactive, liquid 1‐(dialkylamino)‐3,4‐dimethyleneborolanes ( 3 ). These dienes react with activated magnesium to give soluble magnesium adducts 5 which upon treatment with BC1 2 (NR 2 ) (R = Me, i Pr) yield crystalline 3,7‐bis(dialkylamino)‐3,7‐diborabicyclo‐[3.3.0]oct‐1(5)‐enes ( 4 ). The crystal structure of the dimethyl‐amino compound 4a was determined by X‐Ray‐diffraction. The molecule of 4a shows crystallographic C 2 h symmetry with an almost perfectly planar skeleton.