Asymmetric reactions involving isobenzopyrylium ion intermediates

Isobenzopyrylium ions are highly reactive intermediates which have wide applications in synthetic chemistry. A range of catalytic reactions based on isobenzopyrylium, such as 1,2-nucleophilic addition, [4+2] and [3+2] cycloaddition provide a powerful protocol for constructing complex natural and unnatural products. Their asymmetric variations have been less explored, possibly owing to the lack of coordination sites within their planar structures. This mini-review summarizes the asymmetric transformations developed involving isobenzopyrylium ion intermediates. These works are arranged according to the reaction types. The catalytic systems and reaction mechanisms are described. [GRAPHICS] .