Mn(III)-Mediated Reactions of Cyclopropanols with Vinyl Azides: Synthesis of Pyridine and 2-Azabicyclo[3.3.1]non-2-en-1-ol Derivatives
作者:Yi-Feng Wang、Shunsuke Chiba
DOI:10.1021/ja905110c
日期:2009.9.9
to the formation of 2-azabicyclo[3.3.1]non-2-en-1-ol derivatives using a catalytic amount of Mn(acac)(3). These reactions may be initiated by a radicaladdition of beta-keto radicals, generated by the one-electron oxidation of cyclopropanols, to vinyl azides to give iminyl radicals, which would cyclize with the intramolecular carbonyl groups. In addition, versatile transformations of 2-azabicyclo[3.3
A New Versatile Reagent for the Synthesis of Cyclopropylamines Including 4-Azaspiro[2.n]alkanes and Bicyclo[n.1.0]alkylamines
作者:Vladimir Chaplinski、Harald Winsel、Markus Kordes、Armin de Meijere
DOI:10.1055/s-1997-17828
日期:——
The reaction of dialkylcarboxamides 1 with 1 equiv. of methyltriisopropyloxytitanium together with only 1.1 equiv. of a Grignard reagent gives cyclopropylamines 3 in better yields than the previously published method with 2 equiv. of Grignard reagent and 1 equiv. of Ti(OiPr)4. This new protocol can be applied to intramolecular reactions with in situ generation of the Grignard reagent from Ï-bromo-N,N-dimethylhexanamide and methyl Ï-bromohexanoate yielding the expected 1-dimetehylaminocyclo[4.1.0]hexane 15 and the corresponding alcohol 18. Cyclohexylmagnesium bromide or chloride transforms N,N-dibenzylformamide and ethyl acetate to 7-exo-N,N-dibenzylaminonorcarane and 7-exo-hydroxy-7-methylnorcarane. N-Methyl-â-caprolactam 25b and even the strained N-benzylpropiolactam 25a were converted to the spirocyclopropanated heterocycles 26a,b.
Tandem C-C Bond Cleavage of Cyclopropanols and Oxidative Aromatization by Manganese(IV) Oxide in a Direct C-H to C-C Functionalization of Heteroaromatics
作者:Desta Doro Bume、Cody Ross Pitts、Thomas Lectka
DOI:10.1002/ejoc.201501405
日期:2016.1
report a directC–H to C–Cbondfunctionalization of electron-deficient heteroaromatics enabled by mild C–Cbondcleavage of cyclopropanols as a new route to β-aryl carbonyl-containing products. Additionally, as an alternative to using a “catalyst” that requires an excess amount of a sacrificial oxidant for regeneration and/or oxidativearomatization, this paper features manganese(IV) oxide as an inexpensive