Interaction of condensed tetrahydropyrido[4,3-d]pyrimidin-4-ones with dehydrobenzene – synthesis of 6-vinylpyrimidinones fused with five-membered heterocycle containing two or three heteroatoms

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

“…After nucleophilic addition to aryne, a Hoffman-type fragmentation occurred on intermediate 9-145 . In 2018, the same group realized a similar cascade process by using tetrahydropyrido­[4,3- d ]­pyrimidin-4-ones 9-147 condensed with isoxazole, thiazole, thiadiazole, or triazole rings as the substrates, furnishing 6-vinyl-substituted pyrimidones 9-148 fused with the corresponding azole rings via a Hofmann cleavage of the tetrahydropyridine moiety (Scheme b) . In a study carried out by Hoye et al on the reaction of hexadehydro-Diels–Alder (HDDA) aryne with natural products, they showed one example between tropinone ( 9-149 ) and Kobayashi benzyne precursor, leading to the formation of product 9-150 in 66% yield (Scheme c) …”

“…Meanwhile, Voskressensky et al investigated aryne-induced arylation−Hoffman cleavage processes. 694,695 In 2014, they studied the reaction between arynes and 10-carbamoylsubstituted benzo[b] [1,6]naphthyridines 9-144 and obtained 2-vinylquinolines 9-146, albeit in low to moderate yields (Scheme 184a). 694 After nucleophilic addition to aryne, a Hoffman-type fragmentation occurred on intermediate 9-145.…”

“…In 2018, the same group realized a similar cascade process by using tetrahydropyrido [4,3-d]pyrimidin-4-ones 9-147 condensed with isoxazole, thiazole, thiadiazole, or triazole rings as the substrates, furnishing 6-vinyl-substituted pyrimidones 9-148 fused with the corresponding azole rings via a Hofmann cleavage of the tetrahydropyridine moiety (Scheme 184b). 695 In a study carried out by Hoye et al on the reaction of hexadehydro-Diels−Alder (HDDA) aryne with natural products, they showed one example between tropinone (9-149) and Kobayashi benzyne precursor, leading to the formation of product 9-150 in 66% yield (Scheme 184c). 167 In 2015, Voskressensky and co-workers studied the reaction between 4-hydroxymethylisoindolines 9-151 and o-silylaryl triflates and obtained 4-aminomethyl-substituted dihydroisobenzofuran derivatives 9-152 in good to high yields.…”