- Boron-substituted difluorocyclopropanes: New building blocks of gem-difluorocyclopropanes
-
Cycloaddition of difluorocarbene to alkenyl boronates 3 gave boron-substituted gem-difluorocyclopropanes 2 in stereospecific fashion. Upon treatment with lithium carbenoids, cyclopropyl boronates 2 underwent one-carbon homologation to afford a variety of gem-difluorocyclopropanes in good yields.
- Fujioka, Yasutaka,Amii, Hideki
-
supporting information; experimental part
p. 769 - 772
(2009/04/06)
-
- Thermal Rearrangement of N-Arylmethyl- and N-Alkyl-2,2-dihalogenocyclopropyl Imines
-
An extended study of the thermal isomerization of 1-substituted 2,2-dihalogenocyclopropyl imines is reported.The thermolysis of N-arylmethyl-2,2-dichlorocyclopropanecarbaldimines 15a-h produces 2-aryl- 16a-h and 2-aryl-4-chloro-pyridine derivatives 17a-h, while N-cyclopropyl imines 15i, j yielded N-alyklchloropyrroles.The 2,2-dibromocyclopropane analogue undergoes thermolysis at lower temperatures.An ionic mechanism triggered by the halide ion dissociation is proposed for the thermal rearrangement on the basis of a study using deuterated imine 15m, and the effects of additives and solvents.On the other hand, difluorocyclopropyl imine undergoes a homolytic cleavage of cyclopropane 1,3-bond with lower activation energy than the dichlorocyclopropyl imine, and afforded the N-alykl-3-fluoropyrrole derivative preferentially.
- Kagabu, Shinzo,Ando, Chihaya,Ando, Junko
-
p. 739 - 752
(2007/10/02)
-