TY - JOUR
T1 - The combination of 2-NsNH 2/NCS and MeCN as the nitrogen sources for the regio- and stereoselective formation of imidazolines from α,β-unsaturated ketones
AU - Timmons, Cody
AU - Chen, Dianjun
AU - Barney, C. Elizabeth
AU - Kirtane, Sameer
AU - Li, Guigen
N1 - Funding Information:
We gratefully acknowledge financial support from NIH (CA 99995-1) and the Robert A. Welch Foundation (Grant No. D-1361). The contents of this paper are solely the responsibility of the authors and do not necessarily represent the official views of the National Cancer Institute.
PY - 2004/12/20
Y1 - 2004/12/20
N2 - A new nitrogen source combination was found for the regio- and stereoselective diamination of α,β-unsaturated ketones. This combination employs the readily available and inexpensive combination of NCS and 2-NsNH 2 as the electrophilic nitrogen source, and acetonitrile as the nucleophilic nitrogen source, respectively. The reaction is easily performed by mixing olefin, 2-NsNH 2, NCS and 4 Å molecular sieves in freshly distilled acetonitrile at room temperature. The reaction is chemoselective without the formation of any haloamine side products. A new aziridinium ion formed from enones and 2-NsNHCl is suggested to exist and to react with nitrile via a [2+3] cycloaddition mechanism, which is responsible for the excellent regio-, stereoselectivity of the resulting diamination products. The regio-, stereo- and chemoselective imidazolination of enones has been established by using the new combination of 2-NsNH 2/NCS as the electrophilic nitrogen source and MeCN as the nucleophile. The reaction is very convenient to carry out simply by mixing olefin, 2-NsNH 2, NCS and 4 Å molecular sieves in freshly distilled acetonitrile at room temperature. The aziridinium ion formed from the reaction of 2-NsNCl with olefins and the corresponding [2+3] cycloaddition are proposed during the reaction process to control regio- and stereoselectivity.
AB - A new nitrogen source combination was found for the regio- and stereoselective diamination of α,β-unsaturated ketones. This combination employs the readily available and inexpensive combination of NCS and 2-NsNH 2 as the electrophilic nitrogen source, and acetonitrile as the nucleophilic nitrogen source, respectively. The reaction is easily performed by mixing olefin, 2-NsNH 2, NCS and 4 Å molecular sieves in freshly distilled acetonitrile at room temperature. The reaction is chemoselective without the formation of any haloamine side products. A new aziridinium ion formed from enones and 2-NsNHCl is suggested to exist and to react with nitrile via a [2+3] cycloaddition mechanism, which is responsible for the excellent regio-, stereoselectivity of the resulting diamination products. The regio-, stereo- and chemoselective imidazolination of enones has been established by using the new combination of 2-NsNH 2/NCS as the electrophilic nitrogen source and MeCN as the nucleophile. The reaction is very convenient to carry out simply by mixing olefin, 2-NsNH 2, NCS and 4 Å molecular sieves in freshly distilled acetonitrile at room temperature. The aziridinium ion formed from the reaction of 2-NsNCl with olefins and the corresponding [2+3] cycloaddition are proposed during the reaction process to control regio- and stereoselectivity.
KW - Diamination
KW - Diamine
KW - N,N-Dichloro-2-nitrobenzenesulfonamide
KW - NCS
UR - http://www.scopus.com/inward/record.url?scp=9644257337&partnerID=8YFLogxK
U2 - 10.1016/j.tet.2004.10.022
DO - 10.1016/j.tet.2004.10.022
M3 - Article
AN - SCOPUS:9644257337
VL - 60
SP - 12095
EP - 12099
JO - Tetrahedron
JF - Tetrahedron
SN - 0040-4020
IS - 52
ER -