Enantiospecific total synthesis of the putative structure of cryptopyranmoscatone B2

Vaithegi, Kannan; Prasad, Kavirayani R.

doi:10.1016/j.tet.2018.04.011

Cited by 8 publications

(2 citation statements)

References 28 publications

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“…Experiments with a six-membered-ring acetal are consistent with this analysis . For stereoselectivity to occur, addition to the ring-opened aldehyde form of 265 would need to be controlled by either a β-alkoxy group or a δ-OMgCl group (Scheme ).…”

Section: Diastereoselectivities Of Reactions With Carbonyl Compounds ...mentioning

confidence: 99%

“…Experiments with a six-membered-ring acetal are consistent with this analysis. 211 For stereoselectivity to occur, addition to the ring-opened aldehyde form of 265 would need to be controlled by either a β-alkoxy group or a δ-OMgCl group (Scheme 109). The β-alkoxy group would not be expected to control stereoselectivity (as discussed in section 4.2.5.1), and the more distant group likely could not, either.…”

Section: Additions To Alkoxy-substitutedmentioning

confidence: 99%

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Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

et al. 2020

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This review describes the additions of allylmagnesium reagents to carbonyl compounds and to imines, focusing on the differences in reactivity between allylmagnesium halides and other Grignard reagents. In many cases, allylmagnesium reagents either react with low stereoselectivity when other Grignard reagents react with high selectivity, or allylmagnesium reagents react with the opposite stereoselectivity. This review collects hundreds of examples, discusses the origins of stereoselectivities or the lack of stereoselectivity, and evaluates why selectivity may not occur and when it will likely occur. CONTENTS 4.2.5. Additions to β-Substituted Aldehydes 4.2.6. Additions to Aldehydes with Distant Chelating Groups 4.3. Additions to Cyclic Ketones 4.3.1. Alkoxy-Substituted Cyclic Ketones 4.3.2. Additions to Alkoxy-Substituted Five-Membered-Ring Ketones 4.3.3. Additions to Alkoxy-Substituted Four-Membered-Ring Ketones 4.4. Additions of Allylmagnesium Halides to Cyclic Hemiacetals 5. Diastereoselectivity of Reactions of Allylmagnesium Reagents with Carbonyl Compounds by Felkin−Anh Control 5.1. Felkin−Anh Stereoselectivity 5.2. Additions to α-Chiral Acyclic Ketones 5.3. Additions to Chiral Exocyclic Ketones and Aldehydes 5.4. Additions of Allylmagnesium Halides to Chiral Cyclic Ketones Controlled by Felkin−Anh Selectivity 5.5. Additions of Allylmagnesium Halides to Chiral Acyclic Aldehydes 6. Diastereoselectivity of Reactions with Carbonyl Compounds by Steric Approach Control 6.1. Steric Approach Control and Stereoselectivity

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Section: Diastereoselectivities Of Reactions With Carbonyl Compounds ...mentioning

confidence: 99%

Section: Additions To Alkoxy-substitutedmentioning

confidence: 99%

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

et al. 2020

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Cross metathesis with acrylates: N‐heterocyclic carbene (NHC)‐ versus cyclic alkyl amino carbene (CAAC)‐based ruthenium catalysts, an unanticipated influence of the carbene type on efficiency and selectivity of the reaction

Kaczanowska¹,

Trzaskowski

Peszczyńska³

et al. 2020

ChemCatChem

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Olefin metathesis has been widely explored as a handle for chemical diversification, a feature critical across chemical sectors. Cross metathesis (CM) with acrylic acid derivatives is an example of important but, due to the low catalyst's efficiency, industrially non‐utilized transformation. Here we report on systematic evaluation of ruthenium‐based catalysts bearing N‐heterocyclic carbene (NHC) or cyclic alkyl amino carbene (CAAC) ligands in cross metathesis with methyl acrylate. Dramatic influence of the carbene type on the reaction's efficiency and selectivity has been found. Density functional theory (DFT) calculations suggest that the kinetic selectivity is the main factor differentiating NHC‐ and CAAC‐based ruthenium complexes. Productive turnover number (TON) of 49 900 at 10 ppm loading of nitro‐substituted Hoveyda‐Grubbs complex (nitro‐Grela catalyst) was obtained in the studied reaction, representing the highest efficiency reported to date for this transformation. High efficiency and selectivity of nitro‐Grela catalyst was then utilized in cross metathesis of trans‐anethole with 2‐ethylhexyl acrylate to efficiently produce octyl methoxycinnamate (86 % yield), an antioxidant used in sunscreen formulations.

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Six-Membered Ring Systems: With O and/or S Atoms

Santos¹,

Silva²

2020

Progress in Heterocyclic Chemistry

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This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). NoticesKnowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

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Enantiospecific total synthesis of the putative structure of cryptopyranmoscatone B2

Cited by 8 publications

References 28 publications

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin–Anh and Chelation-Control Models

Cross metathesis with acrylates: N‐heterocyclic carbene (NHC)‐ versus cyclic alkyl amino carbene (CAAC)‐based ruthenium catalysts, an unanticipated influence of the carbene type on efficiency and selectivity of the reaction

Six-Membered Ring Systems: With O and/or S Atoms

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