13566-26-2Relevant articles and documents
Ortho substituent effects on transfer of aryl groups from oxygen to carbon in adducts from diaryloxycarbenes and DMAD
Lu, Xiaosong,Warkentin, John
, p. 228 - 234 (2007/10/03)
Diaryloxycarbenes, generated by thermolysis of 2,2-diaryloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines in benzene, reacted with dimethyl acetylenedicarboxylate (DMAD) to afford triesters. The triesters arose by aryl-group transfer from oxygen to carb
Chemistry of cyclic aminooxycarbenes
Couture,Warkentin
, p. 1281 - 1294 (2007/10/03)
A series of oxazolidin-2-ylidenes and one tetrahydro-1,3-oxazin-2-ylidene, generated by thermolysis of Δ3-1,3,4-oxadiazolines in benzene at 90 °C, were intercepted by insertion into the OH bond of phenols. In two cases the initial products rearranged to N-(2-aryloxyethyl)-N-methylformamides. The activation energy for rotation about the amide CN bond of those ultimate products was measured as 20.4 kcal/mol. The aminooxycarbenes reacted with two equivalents of methyl or phenyl isocyanate to give spiro-fused hydantoins. Major products from the reactions of the N-carbonyl carbenes with dimethyl acetylenedicarboxylate or with methyl propiolate were 2-oxazolines resulting from apparent acyl transfers from N to C in the proposed dipolar intermediates; minor products of 1:2 (carbene:trap) stoichiometry were also observed.
SITE SELECTIVITY IN THE REACTIONS OF 1,3-DIPOLES WITH NORBORNADIENE DERIVATIVES
Cristina, D.,Amici, M. De,Micheli, C. De,Gandolfi, R.
, p. 1349 - 1357 (2007/10/02)
The cycloadditions of arylazides, benzonitrile oxides and diphenylnitrile imine to norbornadiene derivatives 1a-c showed varying degree of site- and stereo-selectivity.With dipolarophile 1a arylazides and benzonitrile oxides attack, preferentially, the electron-poor tetrasubstituted double bond, while in the case of 1b and 1c is the substituted double bond which enters the cycloaddition.By contrast, 2-diazopropane and C-phenyl-N-methylnitrone react with the sole tetrasubstituted double bond of 1a-c in stereo- and site-specific cycloadditions.The quantitative evaluation of the two possible reaction paths was performed by glc analysis.The compounds detected were those arising from Diels-Alder cycloreversions of the thermally labile intermediate adducts 2 and 3 (Scheme 1).The results were rationalized on the basis of a qualitative perturbation treatment which considers frontier orbital interactions only.