Efforts toward rapid construction of the cortistatin A carbocyclic core via enyne-ene metathesis

Baumgartner, Corinne; Ma, Sandy; Liu, Qi; Stoltz, Brian M.

doi:10.1039/c004275g

Cited by 35 publications

(7 citation statements)

References 28 publications

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“…Stolz and coworkers utilized a 1:1 mixture of diastereomers in the cascade metathesis that was triggered by the second-generation Grubbs carbene (Scheme 37). 174 As a result, a 37% isolated yield of the desired core ring system was obtained, along with 44% yield of a by-product arising from the other diastereomer. Interestingly, the alternate diastereomer gives a single RCM since the geminal alkene is not able to capture the vinyl carbene intermediate.…”

Section: Cascade Enyne Metathesismentioning

confidence: 98%

5.27 Ene–Yne Metathesis

Diver

Clark

2014

Comprehensive Organic Synthesis II

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Section: Cascade Enyne Metathesismentioning

confidence: 98%

5.27 Ene–Yne Metathesis

Diver

Clark

2014

Comprehensive Organic Synthesis II

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“…Desymmetric enantioselective reduction of 2,2-disubstituted 1,3-diketones has been the most frequently investigated strategy for the synthesis of chiral cyclic 3-hydroxy ketones. Early methods include the oxazaborolidine- ,, (CBS) and enzyme-catalyzed reduction, ,,,− and the transition-metal-catalyzed hydrogenation. ,,− While high to excellent enantioselectivity could be obtained by employing these methods, they suffer at least one of the following drawbacks, such as limited substrate scope, low to moderate diastereoselectivity, and poor stability of the catalysts toward air and moisture. Apart from these, the CBS reduction always requires a slow addition of the substrates or reductants which is problematic for reliable scale up; whereas the enzymatic reduction suffers from troublesome isolation of the products due to the severe foaming and emulsification, and the need to use large volumes.…”

Section: Introductionmentioning

confidence: 99%

Desymmetric Enantioselective Reduction of Cyclic 1,3-Diketones Catalyzed by a Recyclable P-Chiral Phosphinamide Organocatalyst

Qin

Han

2021

J. Am. Chem. Soc.

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The P-stereogenic phosphinamides are a structurally novel skeletal class which has not been investigated as chiral organocatalysts. However, chiral cyclic 3-hydroxy ketones are widely used as building blocks in the synthesis of natural products and bioactive compounds. However, general and practical methods for the synthesis of such chiral compounds remain underdeveloped. Herein, we demonstrate that the P-stereogenic phosphinamides are powerful organocatalysts for the desymmetric enantioselective reduction of cyclic 1,3-diketones, providing a useful method for the synthesis of chiral cyclic 3-hydroxy ketones. The protocol displays a broad substrate scope that is amenable to a series of cyclic 2,2-disubstituted fiveand six-membered 1,3-diketones. The chiral cyclic 3-hydroxy ketone products bearing an all-carbon chiral quaternary center could be obtained with high enantioselectivities (up to 98% ee) and diastereoselectivities (up to 99:1 dr). Most importantly, the reactions could be practically performed on the gram scale and the catalysts could be reused without compromising the catalytic efficiency. Mechanistic studies revealed that an intermediate formed from P-stereogenic phosphinamide and catecholborane is the real catalytically active species. The results disclosed herein bode well for designing and developing other reactions using P-stereogenic phosphinamides as new organocatalysts.

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“…Another impressive application of this strategy was reported by Stoltz and co‐workers in 2010 as part of their study towards the construction of the carbocyclic core of cortistatin A (Figure ) . The key reaction in this work was a cascade dienyne metathesis reaction for the construction of the [5‐6‐7‐6] tricyclic ring system in compound 40 .…”

Section: Introductionmentioning

confidence: 73%

Ruthenium-Catalyzed Metathesis Cascade Reactions in Natural Products Synthesis

Han

2016

Chem. Rec.

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In this account, we provide a brief summary of recent developments in ruthenium-catalyzed metathesis cascade reactions towards the total synthesis of natural products. We also highlight recent progress from our own laboratory regarding the synthesis of securinega alkaloids and humulanolides, which has resulted in the development of novel ruthenium-catalyzed metathesis cascade reactions. Inspired and guided by the pioneering and elegant research conducted in this area, we developed a regio-controlled relay dienyne metathesis cascade reaction and a cyclobutene-promoted RCM/ROM/RCM cascade reaction for the synthesis of securinega alkaloids and humulanolides, respectively.

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Efforts toward rapid construction of the cortistatin A carbocyclic core via enyne-ene metathesis

Cited by 35 publications

References 28 publications

5.27 Ene–Yne Metathesis

5.27 Ene–Yne Metathesis

Desymmetric Enantioselective Reduction of Cyclic 1,3-Diketones Catalyzed by a Recyclable P-Chiral Phosphinamide Organocatalyst

Ruthenium-Catalyzed Metathesis Cascade Reactions in Natural Products Synthesis

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