- Chemoenzymatic epoxidation of alkenes based on peracid formation by a Rhizomucor miehei lipase-catalyzed perhydrolysis reaction
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A chemoenzymatic and selective method for the epoxidation of a series of cyclic and linear alkenes is described. Epoxides have been obtained in moderate to excellent conversions under mild reaction conditions through a two-step sequence, carried out in one-pot. This chemoenzymatic approach is based on a Rhizomucor miehei lipase-catalyzed perhydrolysis reaction to form the corresponding peracid, and subsequent epoxidation of the corresponding alkenes. Reaction parameters with influence in the biotransformation have been optimized specially focusing in the efficient enzymatic peracid formation by means of the correct choice of solvent, oxidant, and peracid precursor. This chemoenzymatic approach has been efficiently applied for the first time, in the regioselective chemical oxidation of (S)-carvone and limonene, both showing an opposite behavior for the oxidation of the internal and external C-C double bond, respectively.
- Méndez-Sánchez, Daniel,Ríos-Lombardía, Nicolás,Gotor, Vicente,Gotor-Fernández, Vicente
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- C-C Bond Cleavage Approach to Complex Terpenoids: Development of a Unified Total Synthesis of the Phomactins
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The rearrangement of carbon-carbon (C-C) single bonds in readily available carbocyclic scaffolds can yield uniquely substituted carbocycles that would be challenging to construct otherwise. This is a powerful and often non-intuitive approach for complex m
- Chang, Stanley,Jurczyk, Justin,Kuroda, Yusuke,Leger, Paul R.,Sarpong, Richmond
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supporting information
p. 15536 - 15547
(2020/10/18)
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- Isolation, synthesis and bioactivity studies of phomactin terpenoids
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Studies of secondary metabolites (natural products) that cover their isolation, chemical synthesis and bioactivity investigation present myriad opportunities for discovery. For example, the isolation of novel secondary metabolites can inspire advances in chemical synthesis strategies to achieve their practical preparation for biological evaluation. In the process, chemical synthesis can also provide unambiguous structural characterization of the natural products. Although the isolation, chemical synthesis and bioactivity studies of natural products are mutually beneficial, they are often conducted independently. Here, we demonstrate the benefits of a collaborative study of the phomactins, diterpenoid fungal metabolites that serve as antagonists of the platelet activating factor receptor. Our isolation of novel phomactins has spurred the development of a bioinspired, unified approach that achieves the total syntheses of six congeners. We also demonstrate in vitro the beneficial effects of several phomactins in suppressing the rate of repopulation of tumour cells following gamma radiation therapy.
- Kuroda, Yusuke,Nicacio, Karen J.,da Silva-Jr, Ildefonso Alves,Leger, Paul R.,Chang, Stanley,Gubiani, Juliana R.,Deflon, Victor M.,Nagashima, Nozomu,Rode, Alexander,Blackford, Katherine,Ferreira, Antonio G.,Sette, Lara D.,Williams, David E.,Andersen, Raymond J.,Jancar, Sonia,Berlinck, Roberto G. S.,Sarpong, Richmond
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p. 938 - 945
(2018/08/28)
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- Selective C-C and C-H Bond Activation/Cleavage of Pinene Derivatives: Synthesis of Enantiopure Cyclohexenone Scaffolds and Mechanistic Insights
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The continued development of transition-metal-mediated C-C bond activation/cleavage methods would provide even more opportunities to implement novel synthetic strategies. We have explored the Rh(I)-catalyzed C-C activation of cyclobutanols resident in hydroxylated derivatives of pinene, which proceed in a complementary manner to the C-C bond cleavage that we have observed with many traditional electrophilic reagents. Mechanistic and computational studies have provided insight into the role of C-H bond activation in the stereochemical outcome of the Rh-catalyzed C-C bond activation process. Using this new approach, functionalized cyclohexenones that form the cores of natural products, including the spiroindicumides and phomactin A, have been accessed.
- Masarwa, Ahmad,Weber, Manuel,Sarpong, Richmond
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supporting information
p. 6327 - 6334
(2015/06/02)
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