Recent advances in total synthesis of natural products by masked ortho-benzoquinones

The Diels-Alder adducts of masked ortho-benzoquinone (MOB) normally perform high regio- and stereoselectivity and are generated under mild conditions. The advantages of MOB include: (a) Containing highly functional moieties: alkene, diene, carbonyl, enone, and dienone; (b) Easily accessible from 2-methoxyphenol derivatives via oxidative dearomatization, and related 2-methoxyphenol easily prepared from commercially available starting materials; (c) The Diels-Alder adducts possessing unique features such as regio- and stereoselectivity and at least four contiguous stereogenic centers in one step. Furthermore, related bicyclo[2.2.2]octenone skeleton can be applied to further complex structure construction by various chemical transformations, such as radical cyclization, oxa-di-pi-methane rearrangement, Beckwith-Dowd rearrangement, hydrogen atom transfer reaction, Cope rearrangement, Wanger-Meerwein rearrangement, carbonyl-ene reaction, aldol reaction, ring opening etc. Among these advantages, MOB system is prospected to continue as an important intermediate for total synthesis of natural products.

Automated summary

The Diels-Alder adducts of masked ortho-benzoquinone (MOB) exhibit high regio- and stereoselectivity and can be formed under mild conditions. MOB has various functional groups, is easily accessible, and can be used for complex structure construction through chemical transformations. Therefore, MOB is considered an important intermediate for total synthesis of natural products.