916664-18-1Relevant academic research and scientific papers
Hydricity-promoted [1,5]-H shifts in acetalic ketenimines and carbodiimides
Alajarin, Mateo,Bonillo, Baltasar,Ortin, Maria-Mar,Sanchez-Andrada, Pilar,Vidal, Angel
, p. 5645 - 5648 (2006)
2-Monosubstituted 1,3-dioxolanes and dithiolanes act as hydride-releasing fragments, transferring intramolecularly their acetalic H atom to the central carbon of ketenimine functions. The presumed products of these migrations, o-quinomethanimines, undergo in situ 6π-electrocyclization. A computational study supports this mechanism and the hydride-shift character of the first step. Carbodiimides were also suitable substrates, although less reactive.
Tandem 1,5-hydride shift/6π electrocyclization of ketenimines and carbodiimides substituted with cyclic acetal and dithioacetal functions: Experiments and computations
Alajarin, Mateo,Bonillo, Baltasar,Ortin, Maria-Mar,Sanchez-Andrada, Pilar,Vidal, Angel
scheme or table, p. 1896 - 1913 (2011/05/05)
N-Aryl ketenimines bearing five- and six-membered cyclic acetal functions - such as 1,3-dioxolane, 1,3-dithiolane, 1,3-dioxane, and 1,3-dithiane systems - at the ortho position of the N-aryl substituent transform on mild thermal treatment into quinolines, through a tandem sequence consisting of a [1,5]-H shift followed by a 6π electrocyclic ring closure. Structurally analogous N-aryl carbodiimides are converted into quinazolines in comparable tandem processes. Similar sequences can be successfully applied to N-thienyl and N-pyrazolyl ketenimines. DFT calculations have established a two-step mechanism for those conversions, consisting of an initial 1,5-hydride shift and subsequent 6π electrocyclization, and confirm the beneficial effect of the acetal function, which gives hydride character to the migrating hydrogen atom. The capability to promote the H shift depends on the type of acetal function (acetal better than dithioacetal), its ring size (five-membered better than six-membered) and the heterocumulenic fragment (ketenimine better than carbodiimide). Changing the benzene ring connecting the acetal and ketenimine functions for a heterocyclic ring has pronounced consequences for the magnitude of the energy barriers. Copyright
Chemoselective reduction of azides catalyzed by molybdenum xanthate by using phenylsilane as the hydride source
Maddani, Mahagundappa R.,Moorthy, Saravana K.,Prabhu, Kandikere R.
supporting information; experimental part, p. 329 - 333 (2010/03/01)
A chemoselective, neutral, and efficient strategy for the reduction of azides to corresponding amines catalyzed by dioxobis(N,N,-diethyldithiocarbamato) molybdenum complex (1, MoO2[S2CNEt2]2) in the presence of phenylsilane is discovered. This chemoselective reduction strategy tolerates a variety of reducible functional groups.
