1987 年 45 巻 1 号 p. 60-70
New approaches to the heterocyclic syntheses through pericyclic reactions are presented in three sections.
(1) The utility of (phenylsulfonyl) propadiene (1) as an allenic dienophile and/or electrophile was revealed by its facile intermolecular cycloaddition reactions with electron-rich dienes, tropone, azaheptafulvenes, and thebaine derivatives, which afforded various heterocyclic compounds including some novel ring systems. (2) trans-4- (Phenylsulfinyl) -3-buten-2-one (29) underwent a new versatile addition-elimination (trans-vinylation) reaction with five-membered heterocycles such as furans, pyrroles, imidazole, pyrazole, and 6- (dimethylamino) fulvene to give excellent yields of the corresponding vinylated compounds. This method combined with the intramolecular Diels-Alder reaction was applied to the synthesis of linearly condensed tricyclic heterocycles like psoralen (31) and the novel aza-analogue of psoralen (38). (3) Intramolecular cycloaddition (ex., Diels-Alder reaction) using allenic dienophiles proceeded with extraordinary ease due to their favorable geometry. These reactions were successfully utilized in the development of new polycyclic lactone synthesis, furan ring transfer (FRT) reactions, tandem intramolecular [2+2] -cycloaddition, [3, 3] -sigmatropic rearrangement, and indole synthesis. Application of some of these new methods to the natural products synthesis is also described.