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Ein neuer Zugang zu 1,2‐ und 1,3‐Diborol
Author(s) -
Gabbert Gernot,
Pritzkow Hans,
Kaschke Michael,
Siebert Walter
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.19941270807
Subject(s) - chemistry , nuclear magnetic resonance spectroscopy , sigmatropic reaction , yield (engineering) , stereochemistry , medicinal chemistry , metallurgy , materials science
A New Approach to 1,2‐ and 1,3‐Diborole Herrn Prof. Dr. Joachim Knappe zum 65. Geburtstag gewidmet. Diaminoborylation of 1,3‐dilithiopropenes leads to the (Z)‐1,3‐bis(diaminoboryl)propenes 4a , b , which are transformed by an amine/chlorine exchange to the (Z)‐1,3‐bis(aminochloroboryl)propenes 5a , b. These react with sodium to yield the 2,5‐dihydro‐1 H ‐1,2‐diboroles 2c , d , whereas the reaction with potassium leads to the 2,3‐dihydro‐1 H ‐1,3‐diboroles 6a , b by rearrangement of the C 3 B 2 skeleton. The constitutions of the heterocycles 2c , d and 6a , b are established by X‐ray structure analyses. Reaction of the 1,2‐diboroles 2c , d with (C 5 H 5 )Co(C 2 H 4 ) 2 leads to the red (1‐borabutadiene)cobalt complexes 3c , d. In 3c a sigmatropic rearrangement is studied by NMR spectroscopy.