Application of environmental-friendly reactions in high-value compound synthesis : synthetic studies towards the total synthesis of dactylolide
Wong, Zhen Zhou
Date of Issue2017
Interdisciplinary Graduate School (IGS)
Nanyang Environment and Water Research Institute
This work aimed to demonstrate the feasibility of two environmental-friendly reactions that developed in Loh’s research group in the racemic synthesis of dactylolide (2), a marine natural product which is a potential candidate for anti-cancer treatment. Syntheses of two major components of dactylolide, namely C1-C8 fragment (C3-2) and C9-C19 fragment (AB-1b-I) were achieved in this study with two key strategies, which were In(OTf)3-catalyzed intramolecular 2,5-oxonium-ene cyclization and Pd-catalyzed direct cross-coupling reaction. Both strategies provided access to southern 2,6-syn-4-exomethylene tetrahydropyran motif and northern conjugated dienoate structure respectively. C9-C19 fragment (AB-1b-I) was convergently synthesized from two parallel syntheses, which provided conjugated aldehyde A2 and homoallylic alcohol B2-2 as precursor for tetrahydropyran synthesis. On the other hand, synthesis of C1-C8 fragment (C3-2) was achieved with a 5-step transformation from epichlorohydrin. This established route utilized convergent strategy, catalytic bond-forming reactions and employed less hazardous chemicals, which showed greener access to target fragments.
DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis