Facile ketene-ketene and ketene-ketenimine rearrangements:: A study of the 1,3-migration of α-substituents interconverting α-imidoylketenes and α-oxoketenimines, a pseudopericyclic reaction

被引:44
作者
Finnerty, JJ [1 ]
Wentrup, C [1 ]
机构
[1] Univ Queensland, Sch Mol & Microbial Sci, Dept Chem, Brisbane, Qld 4072, Australia
关键词
D O I
10.1021/jo035419x
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Theoretical calculations (B3LYP/6-311+G(3df,2p)//B3LYP/6-31G*) of the 1,3 migration of NR2 transforming alpha-oxoketenimines 1 to alpha-imidoylketenes 3 and vice versa indicate that this process is a pseudo-pericyclic reaction with a low activation energy (NH2 97 kJ mol(-1), N(CH3)(2) 62 kJ mol(-1)). The oxoketenimines were found to be more stable (by 18-35 kJ mol(-1)) which is in line with experimental observations. The hindered amine rotation in the amide and amidine moieties adjacent to the cumulenes are important in the migration of the NR2 group, as one of the rotation transition states is close to the 1,3 migration pathway. This gives an interesting potential energy surface with a valley-ridge inflection (VRI) between the orthogonal hindered amine rotation and 1,3 migration transition states. The imidoylketene may also undergo ring closure to an azetinone 5; however, this is metastable, and under the conditions that allow the 1,3-migration, the oxoketenimine 1 will be favored. The imine NH E/Z-interconversion of the ketenimine group takes place by inversion and has a low activation barrier (similar to40 kJ mol(-1)). In all the amidines examined the E/Z-interconversion of the imine function was predicted to be by rotation with a high barrier (>80 kJ mol(-1)), in contrast to all other reported imine E/Z-interconversions which are by inversion.
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页码:1909 / 1918
页数:10
相关论文
共 36 条
[1]   HINDERED ROTATION IN HALOGEN AND PSEUDOHALOGEN CARBON-SUBSTITUTED AMIDES [J].
ALLAN, EA ;
SHAW, KN ;
HOBSON, RF ;
REEVES, LW .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1972, 94 (19) :6604-&
[2]  
[Anonymous], 1995, Exploring Chemistry with Electronic Structure Methods
[3]   Experimental and theoretical studies on the thermal decomposition of heterocyclic nitrosimines [J].
Bartsch, RA ;
Chae, YM ;
Ham, S ;
Birney, DM .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2001, 123 (31) :7479-7486
[4]   DENSITY-FUNCTIONAL THERMOCHEMISTRY .3. THE ROLE OF EXACT EXCHANGE [J].
BECKE, AD .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (07) :5648-5652
[5]  
CHEIKH AB, 1991, J ORG CHEM, V56, P970
[6]   Preparation and pyrolysis of 1-(pyrazol-5-yl)-1,2,3-triazoles and related compounds [J].
Clarke, D ;
Mares, RW ;
McNab, H .
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1, 1997, (12) :1799-1804
[7]   The mechanism of the reaction FH+H2C=CH2→H3C-CFH2.: Investigation of hidden intermediates with the unified reaction valley approach [J].
Cremer, D ;
Wu, AA ;
Kraka, E .
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2001, 3 (05) :674-687
[8]   Linear ketenimines.: Variable structures of C,C-dicyanoketenimines and C,C-bis-sulfonylketenimines [J].
Finnerty, J ;
Mitschke, U ;
Wentrup, C .
JOURNAL OF ORGANIC CHEMISTRY, 2002, 67 (04) :1084-1092
[9]   Facile 1,3-shift of chlorine in a chlorocarbonylketene [J].
Finnerty, J ;
Andraos, J ;
Yamamoto, Y ;
Wong, MW ;
Wentrup, C .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1998, 120 (08) :1701-1704
[10]  
FINNERTY JJ, 2001, THESIS U QUEENSLAND