The acid promoted Petasis reaction of organotrifluoroborates with imines and enamines

Carrera, Diane E.

doi:10.1039/c7cc04397j

Cited by 24 publications

(14 citation statements)

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“…The reaction was also tested for imine electrophiles containing chiral auxiliaries, but no diastereoselectivity could be observed. 145…”

Section: Petasis-type Reactionsmentioning

confidence: 99%

“…In the presence of TFA, both potassium vinyl trifluoroborate and aryl trifluoroborate were successfully used as boron nucleophiles in the reaction with carbamate-protected imines or enamines to give products 126 – 131 in moderate to excellent yield (Scheme ). The reaction was also tested for imine electrophiles containing chiral auxiliaries, but no diastereoselectivity could be observed …”

Section: Petasis-type Reactionsmentioning

confidence: 99%

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Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

2019

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The Petasis boron–Mannich reaction, simply referred to as the Petasis reaction, is a powerful multicomponent coupling reaction of a boronic acid, an amine, and a carbonyl derivative. Highly functionalized amines with multiple stereogenic centers can be efficiently accessed via the Petasis reaction with high levels of both diastereoselectivity and enantioselectivity. By drawing attention to examples reported in the past 8 years, this Review demonstrates the breadth of the reactivity and synthetic applications of Petasis reactions in several frontiers: the expansion of the substrate scope in the classic three-component process; nonclassic Petasis reactions with additional components; Petasis-type reactions with noncanonical substrates, mechanism, and products; new asymmetric versions assisted by chiral catalysts; combinations with a secondary or tertiary transformation in a cascade- or sequence-specific manner to access structurally complex, natural-product-like heterocycles; and the synthesis of polyhydroxy alkaloids and biologically interesting molecules.

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“…The reaction was also tested for imine electrophiles containing chiral auxiliaries, but no diastereoselectivity could be observed. 145…”

Section: Petasis-type Reactionsmentioning

confidence: 99%

Section: Petasis-type Reactionsmentioning

confidence: 99%

Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

2019

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“…The reaction can be applied to a wide range of amines and aldehydes . Also, boronic acids, esters, and even trifluoroborates have been used in this transformation, showing its extensive scope. Furthermore, many highly efficient asymmetric organocatalytic procedures, as well as new and diverse technologies, have been developed in recent years …”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Borono–Mannich Reaction with Pinacol Allenylboronate

Pellegrinet

2020

J. Org. Chem.

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A density functional theory study of the mechanism of the Borono–Mannich reaction using benzylamine and piperidine as representative examples of primary and secondary amines with pinacol allenylboronate is presented. The study shows that both reactions progress through coordination between the boron and the phenolic oxygen. Ring size strain and hydrogen bond activation appear to determine the observed divergent regioselectivity. In the case of benzylamine, the eight-membered ring transition structure that leads to the propargylamine exhibits a hydrogen bond between the hydrogen attached to the nitrogen and the phenolic oxygen (γ-attack), whereas for piperidine a hydrogen bond between the hydrogen on the imine carbon and one of the oxygens of the pinacol group was observed in the six-membered ring transition structure toward the allenylamine (α-attack).

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“…23 Besides excellent functional group compatibility with the great tolerance of air and moisture, PBM multicomponent reaction usually requires aldehydes with an adjacent heteroatom directing group to form a boron "ate" complex where the boronic acid nucleophiles were likely activated for further addition. 24 Recently, Carrera's group 25 reported acidpromoted addition of organotrifluoroborate salts to imines and enamines with the elimination of pendant heteroatom on the iminium intermediate (Scheme 1(a)). Pioneered by Lou and Schaus, 26 catalytic asymmetric PBM reaction provides direct access to induce the enantioenriched α-amino esters by employing alkenyl boronates and biphenol-derived catalysts (Scheme 1(b)).…”

Section: Introductionmentioning

confidence: 99%