DOI: 10.1002/chem.201103435
An Approach to the Regioselective Diamination of Conjugated Di- and
Trienes
Anton Lishchynskyi[a] and Kilian MuÇiz*[a, b]
The direct addition of two nitrogen groups onto 1,3-buta-
dienes constitutes a convenient approach toward higher
functionalized dinitrogenated molecules.[1] This reaction has
been developed by using a series of metal promoters and
can proceed with different regioselectivity depending on the
reaction conditions.[2] In a pioneering demonstration, Sharp-
less et al. reported the use of stoichiometric amounts of bis-
By applying the conditions from the diamination of styr-
enes[10] to 1-phenyl butadiene (1a), the regioselective 1,2-di-
amination of the terminal alkene was accomplished in high
yield (Table 1). The reaction can be conducted readily at
room temperature without requiring an inert atmosphere or
the use of dry solvents. Several different bisimido sources
were examined in this transformation, all of which provided
good yields of the corresponding diamination products 2, al-
though a slightly better result was obtained with Ts2NH
(Table 1, entries 1–6) and this nitrogen source was subse-
quently employed for further reactions. If Ms2NH (Ms=
mesyl) was used as the nitrogen source, preformation of the
ACHTUNGTRENNUNGimidoselenium compounds for the 1,2-diamination of 1,3-
dienes.[3] In the area of palladium chemistry, Bꢀckvall et al.
introduced a regioselective 1,4-addition reaction,[4,5] while
Lloyd-Jones, Booker-Milburn, and Bar demonstrated that
the related 1,2-addition can be carried out under catalytic
conditions with ureas as the nitrogen source.[6,7] An elegant
body of work by Shi et al. demonstrated that diaziridinones
and related nitrogen sources can be employed in the regio-
selective 1,2-diamination of conjugated butadienes and hex-
atrienes under palladium and copper catalysis, respective-
ly.[8,9]
reactive IIII N species was required to achieve a good yield
À
(Table 1, entries 3 vs. 4).
Unexpectedly, if the reaction was performed with a mix-
ture of the E- and Z-stereoisomers of 1a, a similar result to
reactions with geometrically pure starting materials was ob-
tained and the final product was again the (E)-configured
vicinal diamine 2a (Table 1, entries 7 and 8). This apparent
tolerance for geometric mixtures was found to be a general
feature of the reaction. Thus, substrates 1b–d, with different
para substituents on the arene, were prepared as mixtures of
(E)- and (Z)-isomers and submitted to the same reaction
conditions (Table 1, entries 9–12). The products with exclu-
sively the E configuration at the remaining double bond
were again obtained for both bistosylimide and bismesyl-
Very recently, we discovered an unprecedented intermo-
lecular diamination of styrenes by using either a combina-
tion of iodosobenzene diacetate (PhI
tosylimide (Ts2NH), in a 1:2 ratio, or a new hypervalent
iodine(III) reagent, PhI(OAc)(NTs2), in combination with
an additional equivalent of Ts2NH.[10] In general, hyperva-
ACHTUNGRTEN(NUNG OAc)2) and bis-
ACHTUNGTRENNUNG
A
R
ACHTUNGTRENNUNG
lent iodineACHTUNGTRENNUNG(III) reagents are known to effectively oxidize or-
ganic molecules[11] and can be used for the construction of
carbon–nitrogen bonds under attractive metal-free condi-
tions.[12] The unprecedented ability of the new IIII reagent
AHCTUNGTREGiNNNU mide as the nitrogen source. Finally, a mixture of (E)- and
(Z)-1-(2-naphthyl)-1,3-butadiene 1e was separated and both
stereoisomers were independently submitted to the diamina-
tion reaction. As expected, the identical product (E)-2e was
obtained from both reactions with very similar yields
(Table 1, entries 13 and 14).
PhIACHTUNGTRENNUNG(OAc)ACHTUNGTRENNUNG(NTs2) in diamination reactions prompted us to
investigate the related diamination reactions of conjugated
dienes and trienes under metal-free conditions, pursuing dif-
ferent regio- and stereoselectivity. The initial results of this
study are reported herein and include examples of selective
1,4-diamination reactions of conjugated dienes.
Consequently, the corresponding internal 1,3-butadiene
1 f, as a mixture of its (1E,3E)- and (1E,3Z)-isomers, also
led to a single product 2 f (Table 1, entry 15). The expected
(E)-geometry and trans stereochemistry of 2 f were con-
firmed by X-ray analysis (Figure 1).[13] Replacing the methyl
substituent with an electron-demanding ester functionality
allows invertion of the regioselectivity of the reaction to the
other double bond of the conjugated system (Figure 1).
Nevertheless, the reaction remains selective in favor of a vi-
cinal diamination and the stereoselectivity in 2g also re-
mains trans (Table 1, entries 16 and 17, Figure 1), even
though the overall reaction rate diminishes and the reaction
requires an increase in temperature and an excess of the di-
amination reagent to reach full conversion. It is interesting
[a] A. Lishchynskyi, Prof. Dr. K. MuÇiz
Institute of Chemical Research of Catalonia (ICIQ)
Av. Paꢁsos Catalans 16, 43007 Tarragona (Spain)
Fax : (+34)977-920-224
[b] Prof. Dr. K. MuÇiz
Catalan Institution for Research and Advanced Studies (ICREA)
Pg. Lluꢂs Companys 23, 08010 Barcelona (Spain)
Supporting information for this article is available on the WWW
2212
ꢃ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2012, 18, 2212 – 2216