The lithiation of 2-chloroglucal derivatives

Boyd, Ewan; Hallett, Michael R.; Jones, Ray V. H.; Painter, James; Patel, Prakash; Quayle, Peter; Waring, Anita J.

doi:10.1016/j.tetlet.2006.09.087

Cited by 11 publications

(3 citation statements)

References 43 publications

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“…For example, allylation of cholest-3-one ( 620 ) gave the β-allylated product with 86:14 selectivity, although no reaction conditions were provided (Scheme ). Addition of a vinyl anion derived from a glucal gave similar selectivities for alcohol 622 (the figure in this paper shows the opposite configuration C-14, but this figure is likely to be a typographical error considering that 4-cholestene-3-one 620 was used as the starting material for the synthesis of 622 ) …”

Section: Diastereoselectivity Of Reactions With Carbonyl Compounds By...mentioning

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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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: Diastereoselectivity Of Reactions With Carbonyl Compounds By...mentioning

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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“…By and large, the presence of these substituents had the desired effect both in terms of stabilization of the carbene complex yet facilitating our newly devised 'second generation' Dötz reaction. Although these studies proved interesting in terms of developing the co-ordination 16,17 chemistry of chromium and ultimately provided new methodology for the functionalization of carbohydrates 18 it was merely diversionary in terms of developing a strategy towards the synthesis of aflatoxins. Having lost sight of this objective for some time we decided therefore to re-investigate our synthetic strategy to this particular class of natural products.…”

Section: Resultsmentioning

confidence: 99%

Towards aflatoxins: a formal synthesis of aflatoxin B2

Eastham¹,

Ingham²,

Hallett³

et al. 2008

Tetrahedron

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“…2 2-Haloglycals were obtained in addition-elimination processes from the O-acetyl, O-benzyl and O-methyl protected parent glycals to give 2-deoxy-2-chloro-and 2-deoxy-2-bromoglycals in moderate to good yields (35-80%). [3][4][5] Under dehydrative glycosylation of 2-deoxy-2-iodopyranoses with Ph 2 SO/Tf 2 O/TTBP, beside the desired diglycosides, 2-deoxy-2-iodoglycals were also formed. 6 The distribution of the products showed high dependence on the configuration and protecting groups of the sugar derivatives, 2deoxy-2-iodoglycals were obtained in high yields from allo and talo configured 3,4-O-isopropylidene protected derivatives.…”

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confidence: 99%