Synthetic studies toward nortriterpenoids of schisandraceae family. Approach to the construction of functionalized C/D and A/B ring units of micrandilactone C and rubrifloradilactone B

Triterpenoids from the Schisandraceae family: an update

“…Therefore, many research groups have made considerable efforts towards complete syntheses of schinortriterpenoids in the last ten years. Based on the previous achievements, 70-73 some signicant methodological and strategic improvements have been made [74][75][76][77][78][79][80][81]83,[87][88][89] and have led to the accomplishment of the total synthesis of a schinortriterpenoid for the rst time. 82,[84][85][86] Wang and Chen attempted to construct the 7/6/5-fused tricyclic skeleton (279) of lancifodilactone F (258) by using an intramolecular [2 + 2] cycloaddition reaction (268/269) to establish the adjacent C-13/C-14 all-carbon quaternary centers, and an arene-olen meta-photocycloaddition reaction (273/ 275 and 276) to build the 7/6-fused carbocyclic core.…”

“…The synthetic route comprised about 20 reaction steps involving two eneyne RCM reactions as the key steps to construct rings A and C. 81 Subsequently, an approach to the CD ring systems of rubriordilactone B (261) and micrandilactone C (263) was devised based on two intramolecular Diels-Alder reactions (386/389 and 390/393) (Scheme 28). 83 Parrain and co-workers have investigated the collective domino approach towards the synthesis of the core structures of schinortriterpenoids and developed a concise and versatile route to the diastereomeric ABC (402) and ABCD (403) ring systems of lancifodilactone F (258) and micrandilactone B (262), respectively. The keys to the successful construction of the target segments were to carry out a one-pot cascade reaction (401/402), which sequentially established the ABC rings and a quaternary spirocenter at C-10 for lancifodilactone F (258), and to perform an oxa-Michael reaction (402/403) which built ring B of micrandilactone B (262) (Scheme 29).…”

Schinortriterpenoids: A Case Study in Synthetic Design

“…In 2011, Ghosh and co‐workers reported the construction of the aromatic D ring 109 in a one‐pot oxidation/Diels–Alder sequence (Scheme ) . They first obtained alkyne 106 in six steps from glucose derivative 105 .…”

“…In addition, one total synthesis of propindilactone G has been disclosed by Yang and co‐workers . For the aromatic series, the construction of the highly substituted D ring found in rubriflordilactones A and B ( 4 and 9 ) has captured the attention of numerous groups . These efforts have culminated in three total syntheses …”

Total syntheses of schilancidilactones A and B, schilancitrilactone A, and 20-epi-schilancitrilactone A via late-stage nickel-catalyzed cross coupling

“…1 In 2011, Yang and co-workers made a breakthrough in the total synthesis of schindilactone A. 2 Since then, rubriflordilactone A has been synthesized by Li 3 and Anderson, 4 respectively.…”