Synthesis of Adjacent Quaternary Stereocenters by Catalytic Asymmetric Allylboration

Alam, Rauful; Vollgraff, Tobias; Eriksson, Lars; Szabó, Kálmán J.

doi:10.1021/jacs.5b07498

Cited by 131 publications

(66 citation statements)

References 51 publications

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“…Chong5b and Wu have reported on the asymmetric allylboration of cyclic imines using BINOL modified allylboronates whereas the Schaus group8 described the BINOL‐catalyzed asymmetric crotylboration of highly reactive acyl imines. These studies, together with our previous experience,2 suggested that BINOL‐catalyzed allylborations are a promising synthetic method for the catalytic asymmetric allylation of indoles with allylboronic acids.…”

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confidence: 79%

“…Interestingly, commercially available 3 a has been shown to be one of the best catalysts for the asymmetric allylboration of ketones as well 2. Performing the reaction in the absence of methanol substantially decreased the selectivity from 99 % ee to 56 % ee (compare entries 1 and 2).…”

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confidence: 99%

“…Recently, our group described the first catalytic asymmetric synthesis of homoallylic alcohols from γ,γ‐disubstituted allylboronic acids and ketones, furnishing products bearing adjacent quaternary stereocenters 2. Extending this reaction to imines for the synthesis of chiral amines with adjacent stereocenters is important as these motifs are common in drug‐like molecules and natural products 3.…”

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confidence: 99%

“…We envisioned that the catalytic cycle (given in the Supporting Information) of the allylboration of skatole ( 5 a ) would resemble that of our previously disclosed reaction with ketones 2. The crucial additive, MeOH, has a dual role in the catalytic cycle: It is used for the esterification of the RB(OH) 2 group of the allylboronic acid, decreasing its reactivity and silencing the racemic background reaction4c while assisting in the liberation of the catalyst from the product.…”

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confidence: 99%

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Catalytic Asymmetric Allylboration of Indoles and Dihydroisoquinolines with Allylboronic Acids: Stereodivergent Synthesis of up to Three Contiguous Stereocenters

et al. 2016

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The catalytic asymmetric allylboration of cyclic imines with γ,γ‐disubstituted allylboronic acids provides products with adjacent stereocenters in high yield and stereoselectivity. Various electrophiles, including 3,4‐dihydroisoquinolines and indoles, were prenylated in a fully stereodivergent fashion by switching the E/Z geometry of the allylboronate and/or the enantiomer of the BINOL catalyst. 3‐Methylindole provided products with three adjacent stereocenters with high stereoselectivity in one synthetic operation.

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confidence: 79%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Catalytic Asymmetric Allylboration of Indoles and Dihydroisoquinolines with Allylboronic Acids: Stereodivergent Synthesis of up to Three Contiguous Stereocenters

et al. 2016

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“…Szabó et al . reported the synthesis of adjacent quaternary stereocenters in 125 by asymmetric organocatalyzed allylboration of ketones 123 with γ,γ‐disubstituted allylboronic acids 124 (Scheme ) . Full control of the diastereo‐ and enantioselectivity was achieved in a stereodivergent approach by the choice of the BINOL catalyst and the diastereoisomeric prenylboronic acid.…”

Section: Asymmetric Organocatalytic 12‐additionsmentioning

confidence: 99%

Asymmetric Organocatalytic C‐C Bond Forming Reactions with Organoboron Compounds: A Mechanistic Survey

Pellegrinet

2019

Eur J Org Chem

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The recent development of asymmetric organocatalytic C‐C bond forming reactions involving organoboranes has attracted big interest in the synthetic community. Asymmetric organocatalytic additions to enones, aldehydes, ketones, imines, dienes, and related systems can be carried out with different organoboron compounds (boronic acids and esters and trifluoroborate salts) to give products with very good yields and enantiomeric ratios. In particular, many BINOL and α‐hydroxyacid derivatives have been used as chiral organocatalysts. In this review, we describe the mechanisms that have been proposed based on theoretical and experimental studies for asymmetric organocatalytic C‐C bond forming reactions with organoboron compounds. The mechanistic understanding that has been gained should contribute to the progress of this promising area of organic chemistry.

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Recent Advances in the Stereoselective Additions of Allylic Boronates to Carbonyl Compounds

Clement

Hall

2020

Patai's Chemistry of Functional Groups

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The addition of allylboronates to carbonyl compounds remains an invaluable transformation in synthetic organic chemistry for the stereoselective synthesis of a wide variety of substituted homoallylic alcohols. The use of allylboronates is an exceptionally attractive tool, in part due to the stability of organoboron nucleophiles and the inherently high and predictable stereoselectivity consistently observed. Herein, key advances regarding the thermal and catalyzed allylboration of aldehydes and ketones from the past decade are summarized, with a focus on aspects concerning the scope, mechanism, and stereoselectivity. Notably, novel modes of activation are described for both enantioenriched α‐substituted allylboronates and catalytic enantioselective additions of achiral boronates using chiral protic acids and organocatalysts. A number of innovative metal‐catalyzed enantioselective borylation approaches to allylboronates and their subsequent use as substrates, including bimetallic double allylation reagents, are also highlighted. The current innovative progress and limitations in the field of carbonyl allylboration are discussed.

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Synthesis of Adjacent Quaternary Stereocenters by Catalytic Asymmetric Allylboration

Cited by 131 publications

References 51 publications

Catalytic Asymmetric Allylboration of Indoles and Dihydroisoquinolines with Allylboronic Acids: Stereodivergent Synthesis of up to Three Contiguous Stereocenters

Catalytic Asymmetric Allylboration of Indoles and Dihydroisoquinolines with Allylboronic Acids: Stereodivergent Synthesis of up to Three Contiguous Stereocenters

Asymmetric Organocatalytic C‐C Bond Forming Reactions with Organoboron Compounds: A Mechanistic Survey

Recent Advances in the Stereoselective Additions of Allylic Boronates to Carbonyl Compounds

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