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Conjugate addition – enantioselective protonation reactions

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ABSTRACT

The addition of nucleophiles to electron-deficient alkenes represents one of the more general and commonly used strategies for the convergent assembly of more complex structures from simple precursors. In this review the addition of diverse protic and organometallic nucleophiles to electron-deficient alkenes followed by enantioselective protonation is summarized. Reactions are first categorized by the type of electron-deficient alkene and then are further classified according to whether catalysis is achieved with chiral Lewis acids, organocatalysts, or transition metals.

No MeSH data available.


Sibi’s addition of arylboronic acids to α-methylaminoacrylates.
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C14: Sibi’s addition of arylboronic acids to α-methylaminoacrylates.

Mentions: Inspired by previous reports on the synthesis of α-amino esters using rhodium(I) catalysis, Sibi and co-workers investigated the enantioselective synthesis of β-amino esters 62 via the addition of arylboronic acids 47 to α-methylaminoacrylates 61 (Scheme 14) [35]. The authors identified (S)-difluorphos (44, Fig. 2) and phthalimide as the optimal ligand and proton source combination, respectively. Additionally, the bulky tert-butyl ester was necessary for achieving both good reactivity and enantioselectivity. All of the arylboronic acids investigated, except 4-methylphenylboronic acid, added in good yield and enantioselectivity (70–95% yield, 92:8 to 95.5:4.5 er).


Conjugate addition – enantioselective protonation reactions
Sibi’s addition of arylboronic acids to α-methylaminoacrylates.
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4979737&req=5

C14: Sibi’s addition of arylboronic acids to α-methylaminoacrylates.
Mentions: Inspired by previous reports on the synthesis of α-amino esters using rhodium(I) catalysis, Sibi and co-workers investigated the enantioselective synthesis of β-amino esters 62 via the addition of arylboronic acids 47 to α-methylaminoacrylates 61 (Scheme 14) [35]. The authors identified (S)-difluorphos (44, Fig. 2) and phthalimide as the optimal ligand and proton source combination, respectively. Additionally, the bulky tert-butyl ester was necessary for achieving both good reactivity and enantioselectivity. All of the arylboronic acids investigated, except 4-methylphenylboronic acid, added in good yield and enantioselectivity (70–95% yield, 92:8 to 95.5:4.5 er).

View Article: PubMed Central - HTML - PubMed

ABSTRACT

The addition of nucleophiles to electron-deficient alkenes represents one of the more general and commonly used strategies for the convergent assembly of more complex structures from simple precursors. In this review the addition of diverse protic and organometallic nucleophiles to electron-deficient alkenes followed by enantioselective protonation is summarized. Reactions are first categorized by the type of electron-deficient alkene and then are further classified according to whether catalysis is achieved with chiral Lewis acids, organocatalysts, or transition metals.

No MeSH data available.