New progress in theoretical investigation on
N-aziridinyl imine compounds forming triquinane
Yan Qiao and Ke-Li Han*
Org. Biomol. Chem., 2014,12, 1220-1231
Org. Biomol. Chem., 2014,12, 1220-1231 DOI: 10.1039/C3OB42115E
a research team leading by Prof. Han Ke-Li in Dalian Institute of
Chemical Physics, Chinese Academy of Sciences has made new progress in
the reactions of N-aziridinyl imine compounds forming triquinanes. Their
accomplishment “Theoretical investigations toward the tandem reactions
of N-aziridinyl imine compounds forming triquinanes via
trimethylenemethane diyls: mechanisms and stereoselectivity” was
published on Organic & Biomolecular Chemistry (2014, 12, 1220-1231) as a
Linearly-fused triquinanes represent an important class of natural
products, and thus they have attracted continuous attention from
synthetic chemists. Lee et al. recently reported a direct tandem
intramolecular cycloaddition reactions of N-aziridinyl imine compounds
to give triquinane products at mild temperature 110˚C. Nevertheless, the
detailed reaction mechanism as well as the stereoselectivity remains
elusive. This makes it difficult to rational design more effcient
substrates to improve the yield and stereoselectivity. Prompted by these
questions, Prof. Han Ke-Li et al. performed a theoretical investigation
on this kind of reaction using density-functional theory. The calculated
results reveal that the whole reaction consists of four steps: N-aziridinyl
imine ring opening, 1,3-dipolar cycloaddition, extrusion of N2, and
[3+2] cycloaddition. The extrusion of N2 can give rise to singlet and
triplet trimetheneylmethane diyls, and the intramolecular [3+2]
cycloaddition of singlet trimetheneylmethane diyl is the preferred
reaction pathway since it requires relatively lower activation energy.
In addition, it also show that there are two cycloaddition modes for
singlet trimetheneylmethane diyl, producing two stereoselective
products. And the calculated activation energies are in agreement with
the experimental results. This work not only provides mechanistic
insights into this important diyl trapping reactions, but also clarifies
the stereocontrol factors. So it should be helpful for people to
rational design more efficient reaction substrate.
In recently years, Prof.
Han Ke-Li’s group has done a lot of theoretical researches on organic
reactions, and series of achievements have been published on J. Org.
Chem., Org. Biomol. Chem. et al..
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