Addition/Correction
Correction to Synthesis of Heterocycles via Pd-Ligand Controlled
Cyclization of 2‑Chloro‑N‑(2-vinyl)aniline: Preparation of Carbazoles,
Indoles, Dibenzazepines, and Acridines
Dmitry Tsvelikhovsky and Stephen L. Buchwald*
J. Am. Chem. Soc. 2010, 132, 14048−14051. DOI: 10.1021/ja107511g
S
* Supporting Information
(Table 1 in original manuscript) occurred in 70% isolated yield
(99% reported).
e recently reported a synthesis of carbazoles (8),
Wacridines (9), and dibenzazepines (1) from common
precursor 7 via Pd-catalysis. The catalyst based on L2 gave
exclusively 1, while catalysts based on L3 and L4 selectively
formed 8 and 9, respectively (Figure 1).
In summary, the formation of 1 from 7 is largely selective,
but the yields may be somewhat lower than what is reported.
The reactions that form 8 and 9, in contrast to what we
originally reported, form mixtures of products with the major
isomer being the one indicated in our published manuscript.
The supposition that catalysts based on L2−L4 each produce a
single product is not correct. We apologize for these errors and
for any inconvenience to others that this may have caused. We
thank Drs. Thomas Maimone and Meredeth McGowan for
their invaluable assistance.
ASSOCIATED CONTENT
* Supporting Information
Experimental details for the preparation and characterization of
2. This information is available free via the Internet at http://
■
S
Figure 1. Previously reported ligand-controlled cyclizations of 2-
chloro-N-(2-vinyl)aniline (7).
Upon re-examination of both the Pd-L3 and Pd-L4 catalyst
systems, we have found that these systems are not 100%
selective as we previously reported. The reaction of 7 using L3
1
gave 8 in 55% isolated yield (94% reported). The H NMR
spectrum of the crude reaction mixture showed 8, 1, and 9 in
an approximate ratio of 1.0:0.25:0.20. This product distribution
was largely insensitive to temperature (90−110 °C range) and
other tested variables.
The reaction of 7 using L4 gave 9 in 45% isolated yield (87%
reported). The 1H NMR of the crude reaction mixture showed
9, 1, 8, and a previously unidentified compound in an
approximate ratio of 1.0:0.18:0.05:0.60. The latter was
identified as dimer 2 (X-ray). Again, the product ratio was
insensitive to slight variations in the reaction conditions.
The reaction of 7 using L2 furnished dibenzazepine 1 in 80%
isolated yield (99% reported) and with good selectivity (∼90%)
1
by H NMR analysis of the crude reaction mixture. The one-
pot conversion of 2-chloroaniline and 2-bromostyrene to 1
Figure 2. Dimeric dibenzazepine side product 2 (see Supporting
Information).
Published: September 25, 2012
© 2012 American Chemical Society
16917
dx.doi.org/10.1021/ja3066094 | J. Am. Chem. Soc. 2012, 134, 16917−16917
Tsvelikhovsky, Dmitry
