Beilstein J. Org. Chem.2019,15, 1257–1261, doi:10.3762/bjoc.15.122
recently designed an efficient synthesis for one of the simplest BN-PAHs, namely BN-phenanthrene 1a [23]. We are interested in evaluating the reactivity [24] and properties of 1a in greater detail as this could provide valuable information that leads to a better understanding of the behaviour of BN
-aromatics. Interestingly, 1a turned out to be weakly fluorescent [23], in contrast to other BN-phenanthrene isomers described previously [25][26]. The presence of aryl or amino substituents at C1, which can be introduced via bromination and subsequent palladium-catalyzed cross coupling, does not have a
PDF
Graphical Abstract
Figure 1:
BN-phenanthrene 1a and synthesis of substituted derivatives proposed in this work.
Beilstein J. Org. Chem.2013,9, 761–766, doi:10.3762/bjoc.9.86
isomerisation reaction, 22 kcal mol−1, should be high enough for an experimental observation in solution. However, in solution the dimerisation of 3 is computed to have a very low barrier (3 kcal mol−1), and thus 3 is expected to be a short-lived reactive intermediate.
Keywords: ab initio; azaborine; BN
aromatics; Dewar isomer; reaction mechanism; Introduction
The barrier for ring opening of Dewar benzene (1) to yield benzene (2) is high enough to give this benzene valence isomer a half life of about two days [1] at room temperature despite the significant exothermicity (60–70 kcal mol−1) of the
PDF
Graphical Abstract
Scheme 1:
Isomerisation of bicyclo[2.2.0]hexa-1,3-diene, Dewar benzene (1), to benzene (2) and of 2-aza-3-bor...