C O M M U N I C A T I O N S
Table 2. Intramolecular Diamination of Olefinsa
Scheme 2
sulfamide nitrogen to Cu(OAc)2, providing intermediate 17. Migra-
tory insertion would then form the new sp3 N-C bond, giving 18.4,7
The organocopper species 18 may undergo ligand exchange with
the remaining nitrogen, followed by reductive elimination, providing
sulfamide 2a. Yet another mechanistic scenario would involve
homolysis of the carbon-copper bond of 18 followed by copper-
(II)-promoted oxidative coupling for N-C bond formation.
The method communicated herein expands the olefin diamination
concept to include an intramolecular process and new copper(II)
chemistry, thereby yielding a number of cyclic diamines. The cyclic
sulfamide adducts are valuable entities to medicinal chemistry and
material science,8 and the free diamine is easily liberated using
LiAlH4. Further expansion of the substrate scope and mechanism
studies are underway.
Acknowledgment. This research was supported by the Uni-
versity at Buffalo, SUNY and the donors of the Petroleum Research
Fund (PRF 40968-G1).
Supporting Information Available: Procedures and characteriza-
tion data for all new products. This material is available free of charge
a Reaction conditions: 3 equiv of Cu(OAc)2, 2 equiv of K2CO3, DMF
(0.08-0.1 M), DMSO (10 equiv), 90 °C, 48 h. b Selectivity determined by
analysis of the crude 1H NMR spectrum and by amount of the isolated
adducts. c Yield refers to amount of product isolated by chromatography
on silica gel. d Reaction was conducted at 120 °C.
References
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Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford,
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Chem., Int. Ed. 1998, 37, 2580.
that an acid-sensitive group (a benzylic, allylic secondary alcohol)
can survive the mild diamination reaction conditions.
The isoquinoline 12 was formed in 83% yield upon cyclization
of the 2-allylbenzylamine sulfamide 11. Cyclization of the branched
benzylic sulfamide 13 led to a 1.2:1 mixture of diastereomeric
isoquinolines 14 and 15, albeit only in 34% yield. Reaction of
substrate 13 is both entropically and sterically challenging, and side
reactions included loss of the substrate’s sulfamide group (Bn-
NHSO2-) under the reaction conditions.
The trans-methyl-1,2-disubstituted olefin derivative of 3 (R )
Me) and N-benzyl-N′-(2-cyclopent-2-enylethyl)sulfamide failed to
provide the diamination products; primarily starting compounds with
and without the sulfamide group were obtained. Clearly, steric
hindrance on the terminal position of the olefin affects the reactivity
of the substrate.
(2) Kolb, H. C.; VanNieuwenhze, M. S.; Sharplesss, K. B. Chem. ReV. 1994,
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The free diamine can be obtained by reduction of the sulfamide
with LiAlH4 (cf. 2a f 16, 93% yield).
A working hypothesis for the diamination mechanism is proposed
in Scheme 2. The reaction is likely initiated by coordination of the
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