Cyclopropanes are both valuable building blocks in synthetic chemistry and important
functional moieties existing in natural products and biologically active molecules.
The Simmons–Smith cyclopropanation has become a very useful and reliable method for
the synthesis of cyclopropanes from olefins. Aiming at the development of tunable
and highly reactive zinc carbenoids, Shi and coworkers proposed an effective strategy
for the generation of zinc carbenoids RXZnCH2I by reacting RXH with an appropriate organozinc reagent, which allows tuning the
reactivity of RXZnCH2I reagents simply by changing the modifier RXH. This type of carbenoid reagent- is
known as Shi carbenoid or reagent and has been found to be highly effective for each
type of olefins, which attracts intensive attention and results in numerous successful
applications in the synthesis of complex molecules, as well as important cyclopropane
building blocks. Significantly, the asymmetric Simmons–Smith cyclopropanation of unfunctionalized
olefins has also been achieved using a chiral modifier.
Keywords
Cyclopropane - Simmons–Smith reaction - Zinc carbenoids - Shi carbenoids - Asymmetric
cyclopropanation
