Compendium of Cycloaddition Reactions under High Pressure

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

“…Another attempt to optimize the reaction conditions was based on the use of the high-pressure method. This approach offers some advantages, especially in the case of cycloaddition reactions [ 18 ]. To the best of our knowledge, reactions of thioketones under high-pressure conditions have never been studied.…”

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

“…Another attempt to optimize the reaction conditions was based on the use of the high-pressure method. This approach offers some advantages, especially in the case of cycloaddition reactions [ 18 ]. To the best of our knowledge, reactions of thioketones under high-pressure conditions have never been studied.…”

Total Synthesis of Transtaganolide E and F: Insight in the Biosynthesis of the Transtaganolides

“…All attempts to convert 27 to 12 / 13 through an intramolecular Diels–Alder reaction by using thermal or Lewis acid catalyzed conditions failed illustrating the importance of a 5‐halo substituent to activate the 2‐pyrone ring system (as in 15 ) 12. However, high pressure conditions were found to be successful for the intramolecular Diels–Alder reaction,14 at 1.5 GPa and 50 °C in MeCN the cyclization of 27 proceeded smoothly, and tricyclic lactone 12 / 13 was obtained as an inseparable 2:1 diastereomeric mixture.…”

Cross-Diels−Alder Reactions of 6-Oxo-1-Sulfonyl-1,6-Dihydropyridine-3-Carboxylates

“…This strategy has been effective for [4 + 2] cycloadditions . The highly negative volume of activation of the Diels−Alder reaction led us to consider high pressures as an alternative approach . 2,3-Dimethylbuta-1,3-diene ( 4a ), cyclopenta-1,3-diene ( 4b ), and cyclohexa-1,3-diene ( 4c ) were selected as classical electron-rich dienes.…”

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

“…Another attempt to optimize the reaction conditions was based on the use of the high-pressure method. This approach offers some advantages, especially in the case of cycloaddition reactions [ 18 ]. To the best of our knowledge, reactions of thioketones under high-pressure conditions have never been studied.…”

Total Synthesis of Transtaganolide E and F: Insight in the Biosynthesis of the Transtaganolides

“…All attempts to convert 27 to 12 / 13 through an intramolecular Diels–Alder reaction by using thermal or Lewis acid catalyzed conditions failed illustrating the importance of a 5‐halo substituent to activate the 2‐pyrone ring system (as in 15 ) 12. However, high pressure conditions were found to be successful for the intramolecular Diels–Alder reaction,14 at 1.5 GPa and 50 °C in MeCN the cyclization of 27 proceeded smoothly, and tricyclic lactone 12 / 13 was obtained as an inseparable 2:1 diastereomeric mixture.…”

Cross-Diels−Alder Reactions of 6-Oxo-1-Sulfonyl-1,6-Dihydropyridine-3-Carboxylates

“…This strategy has been effective for [4 + 2] cycloadditions . The highly negative volume of activation of the Diels−Alder reaction led us to consider high pressures as an alternative approach . 2,3-Dimethylbuta-1,3-diene ( 4a ), cyclopenta-1,3-diene ( 4b ), and cyclohexa-1,3-diene ( 4c ) were selected as classical electron-rich dienes.…”

Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

“…Another attempt to optimize the reaction conditions was based on the use of the high-pressure method. This approach offers some advantages, especially in the case of cycloaddition reactions [ 18 ]. To the best of our knowledge, reactions of thioketones under high-pressure conditions have never been studied.…”

Total Synthesis of Transtaganolide E and F: Insight in the Biosynthesis of the Transtaganolides

“…All attempts to convert 27 to 12 / 13 through an intramolecular Diels–Alder reaction by using thermal or Lewis acid catalyzed conditions failed illustrating the importance of a 5‐halo substituent to activate the 2‐pyrone ring system (as in 15 ) 12. However, high pressure conditions were found to be successful for the intramolecular Diels–Alder reaction,14 at 1.5 GPa and 50 °C in MeCN the cyclization of 27 proceeded smoothly, and tricyclic lactone 12 / 13 was obtained as an inseparable 2:1 diastereomeric mixture.…”

Cross-Diels−Alder Reactions of 6-Oxo-1-Sulfonyl-1,6-Dihydropyridine-3-Carboxylates

“…This strategy has been effective for [4 + 2] cycloadditions . The highly negative volume of activation of the Diels−Alder reaction led us to consider high pressures as an alternative approach . 2,3-Dimethylbuta-1,3-diene ( 4a ), cyclopenta-1,3-diene ( 4b ), and cyclohexa-1,3-diene ( 4c ) were selected as classical electron-rich dienes.…”