Recent Advances in Natural Product Synthesis by Using Intramolecular Diels−Alder Reactions

Functionalisation of Macroheterocycles with Preserving and Changing Their Sizes

“…Diels-Alder. [129] A macrocyclization reaction of compound (264) in synthesis of [(11R)-(-)-8-epi-11-hydroxyaphidicolin] (262) that is an unnatural derivative of tetracyclic diterpene (+)-aphidicolin (263) isolated from Cephalosporium aphidicola fungus as a potential anticancer agent led to the formation of polyfunctional E,E,Z-triene (265) involved in a tandem of highly stereoselective reactions, such as the trans-annular Diels-Alder sequence and aldolization into tetracyclic compound (266) as a precursor of (262) (Scheme 58). [130,131] Macroheterocycles Functionalization Accompanied by Preservation and Changing Their Size The Diels-Alder reaction is also used in the key step of the formation of hexaphenylene (267) as a representative with the carbon allotropic modification "cubic graphite", the conical cavity of which can be used as the "host" in molecular associates, and compound (267) itself -as a building block for porous solids.…”

A reação de Diels-Alder no início do século vinte um

“…Tadano e colaboradores, 77 e depois Juhl e Tanner 78 apresentaram excelentes revisões sobre a reação de Diels-Alder intramolecular (IMDA) e algumas recentes aplicações na síntese total de produtos naturais.…”

Investigation of the Pathway for Intramolecular Electron Transfer in Anodic [2 + 2] Cycloaddition Reactions

“…For example, 3,4-dihydro-2H-pyran (1) was oxidized at the anode and the resulting radical cation reacted with 4-allylanisole (2) to give the corresponding cycloadduct (3) (Scheme 1). When allylbenzene (4) was used instead of 4-allylanisole (2), the cycloadduct (5) was not obtained even in combination with anisole (6). Therefore, we concluded that the methoxyphenyl ring served as a "redox tag" that was oxidized to form the cyclobutane ring and was then reduced to complete the overall reaction (Scheme 2).…”