Total Synthesis of Cryptopleurine and Its Analogues

Abstract

Total synthesis of phenanthroquinolizidine alkaloid cryptopleurine was achieved in 8 steps from commercially available 2-pyridinecarboxaldehyde and epoxide derived from methyl eugenol. The key intermediate 5 enables the divergent synthesis of cryptopleurine derivatives by late-stage installation of various substituents on the C-ring.

Recent Advances in Pd‐Catalyzed Suzuki‐Miyaura Cross‐Coupling Reactions with Triflates or Nonaflates

“…With this, a late‐stage installation of various electron‐donating and ‐withdrawing aryl substituents was possible via SM cross‐coupling using standard reaction conditions with Pd(PPh 3 ) 4 as a catalyst and K 2 CO 3 as a base in a DME/H 2 O solvent mixture at 80 °C (Scheme 40). [58] …”

“…With this, a late-stage installation of various electron-donating and -withdrawing aryl substituents was possible via SM cross-coupling using standard reaction conditions with Pd(PPh 3 ) 4 as a catalyst and K 2 CO 3 as a base in a DME/ H 2 O solvent mixture at 80 °C (Scheme 40). [58] A group of novel racemic nicotinic ligands, where SM cross-coupling with vinyl triflates was also utilized as a key step, was introduced by De Micheli and coworkers. They were able to synthesize three different derivatives using diverse arylboronic acids, in a Pd-(PPh 3 ) 4 , anhydrous LiCl, Na 2 CO 3 and DME reaction system (Scheme 41).…”

Catalyzing the Development of Self-Efficacy and Science Identity: A Green Organic Chemistry CURE

“…46 An epoxidation reaction was chosen, as epoxides are universally studied in a wide array of chemistry applications, ranging from polymer and material chemistry 47−49 to biochemical reactions catalyzed by cytochrome P450s. 50−52 Epoxides also have applications as useful synthetic intermediates for preparing diverse carbon skeletons, 53,54 especially given their straightforward preparation from alkenes. However, alkene epoxidation has historically used conditions that are environmentally unfriendly or dangerous.…”

“…The reaction chosen for optimization was a green epoxidation reaction that worked well for reactive alkene substrates but was slow for deactivated alkenes, like trans -stilbene . An epoxidation reaction was chosen, as epoxides are universally studied in a wide array of chemistry applications, ranging from polymer and material chemistry − to biochemical reactions catalyzed by cytochrome P450s. − Epoxides also have applications as useful synthetic intermediates for preparing diverse carbon skeletons, , especially given their straightforward preparation from alkenes. However, alkene epoxidation has historically used conditions that are environmentally unfriendly or dangerous. , Efforts in the literature have addressed these environmental concerns, but green epoxidation procedures have been limited to more “activated” alkene substrates, such as alkenes that have few electron-withdrawing groups (EWGs) (e.g., styrene), have electron-donating groups (EDGs) (e.g., cyclohexene), and/or involve the use of metal catalysts. , There are fewer literature examples of using deactivated alkene derivatives, such as alkenes with multiple EWGs ( trans -stilbene) using metal-free green procedures. , …”