Regioselective trifluoromethylation–cyclization: A method for copper-catalyzed trifluoromethylation–cyclization of simple enynes using the C![[BOND]](http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8ff.gif)
C triple bond as a nucleophile is reported for the first time (see scheme). The reaction proceeds efficiently in a highly regioselective manner to give various 5- or 6-exo-dig carbocycles and heterocycles in moderate to high yields.
The unexpected 1,2-addition of various alkyl Grignard reagents to nitro groups is described. A simple treatment of a 2-nitropyridine N-oxide with an alkyl Grignard reagent results in a 2-[alkyl(hydroxy)amino]pyridine N-oxide as the result of a 1,2-addition to the nitro group. Moreover, 2-(alkylamino)pyridine N-oxides can also be obtained from this 1,2-addition after a reductive workup by using NaBH4/FeCl3. This work shows another facet of the reactions between alkyl Grignard reagents and nitro groups, and provides a simple method for the formation of carbon–nitrogen bonds without a transition metal catalyst.
The unexpected 1,2-addition of alkyl Grignard reagents to nitro groups is described. 2-[Alkyl(hydroxy)amino]pyridine N-oxides and 2-(alkylamino)pyridine N-oxides can be prepared by 1,2-addition of alkyl Grignard reagents to the nitro group of 2-nitropyridine N-oxides. This new reaction between alkyl Grignard reagents and nitro groups provides a simple method for carbon–nitrogen bond formation.