Conversion of optically active hydrindanone to (+)-bakkenolide-A
Taichi Kusakabe1, Keisuke Kato, Satoshi Motodate
1Faculty of Pharmaceutical Sciences, Toho University, Chiba, Japan.
Researchers achieved a total synthesis of (+)-bakkenolide-A using a novel asymmetric cyclization-carbonylation reaction. This method efficiently constructed the key intermediate and the spirolactone moiety, advancing natural product synthesis.
Area of Science:
- Organic Chemistry
- Natural Product Synthesis
Background:
- Bakkenolide-A is a natural product with potential biological activities.
- Efficient synthetic routes are crucial for accessing complex molecules like bakkenolide-A.
Purpose of the Study:
- To achieve the total synthesis of (+)-bakkenolide-A.
- To develop and utilize an asymmetric cyclization-carbonylation reaction for key intermediate synthesis.
Main Methods:
- Asymmetric cyclization-carbonylation reaction for key intermediate 4 preparation.
- Mitsuhashi's protocol for diastereoselective spirolactone moiety construction.
Main Results:
- Successful total synthesis of (+)-bakkenolide-A.
- Efficient preparation of key intermediate 4.
- Diastereoselective construction of the spirolactone core.
Conclusions:
- The developed asymmetric cyclization-carbonylation strategy is effective for synthesizing complex natural products.
- Mitsuhashi's protocol is a valuable tool for constructing spirolactone systems.
Related Concept Videos
03:08Hydroboration-Oxidation of Alkenes
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
02:36Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
00:43Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation
02:40Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.