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Synthesis and Structure of Novel Organocycloborates
Author(s) -
Braunschweig Holger,
D'Andola Giovanni,
Welton Tom,
White Andrew J. P.
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500760
Subject(s) - hydroboration , boron , yield (engineering) , ring (chemistry) , chemistry , nuclear magnetic resonance spectroscopy , medicinal chemistry , stereochemistry , organic chemistry , materials science , metallurgy , catalysis
A series of α, ω ‐boryl(bromo)alkanes of the general formula R 2 B(CH 2 ) n Br ( n =3, 4, 5, 6) was obtained in high yield following a standard hydroboration protocol. Upon treatment with Mg turnings and formation of the respective Grignard species, all alkanes with n =4 to 6 underwent an unprecedented boron‐centered cyclisation reaction with formation of boratacyclopentanes, ‐hexanes, and ‐heptanes, respectively. All new compounds were isolated in high yields as colourless, crystalline materials and characterised in solution by multinuclear NMR spectroscopy. Four representative examples were chosen for X‐ray diffraction studies, thus providing the first structurally characterised ring systems of that size at a tetraalkyl borate centre.