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Pathways for the cyclotetramerization of dibenz[c,e][1,2]azaborine, a BN‐phenanthryne
Author(s) -
Bettinger Holger F.,
Müller Matthias
Publication year - 2015
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3390
Subject(s) - chemistry , basis set , valence (chemistry) , tetramer , low energy , derivative (finance) , thermal decomposition , stereochemistry , computational chemistry , density functional theory , medicinal chemistry , organic chemistry , physics , atomic physics , financial economics , economics , enzyme
The BN‐phenanthryne dibenz[c,e][1,2]azaborine (9) was previously inferred as a reactive intermediate in the solution phase thermolysis of 9‐azido‐9‐borafluorene by isolation of its cyclic tetramer. The mechanism of the cyclotetramerization of BN‐phenanthryne (9) is investigated using a meta‐generalized gradient approximation density functional (TPSS‐D3) in conjunction with a polarized split valence basis set and single energy points using a double‐hybrid functional (B2PYLP‐D3) with a polarized triple‐zeta basis set. The most favorable mechanism involves the dimerization of 9 to diazadiboretidine derivative 10 , followed by dimerization of 10 for which two different pathways were identified computationally. The more favorable one involves a B 4 N 4 bicyclo[4.2.0]octa‐2,4,7‐triene intermediate . An alternative mechanism, slightly higher in energy, proceeds through a B 4 N 4 cube isomer that lies in an unexpectedly deep potential energy minimum. The low barriers of dimerization of 10 make it a short lived reactive intermediate that likely is too reactive to be trapped by the still more reactive cyclic iminoborane 9. Copyright © 2014 John Wiley & Sons, Ltd.