Simple Chiral Pyrrolidine–Pyridine‐Based Catalysts for Highly Enantioselective Michael Addition to Nitro Olefins

Xu, Da‐Zhen; Shi, Sen; Wang, Yongmei

doi:10.1002/ejoc.200900716

Cited by 48 publications

(8 citation statements)

References 56 publications

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“…In effect, proline can function as bifunctional asymmetric catalyst and thereby became successful for facilitating stereoselective chemical transformations similar to enzymatic catalysis. Thus, the use of proline and the small molecules derived from it has been a major breakthrough in the field of organocatalysis to synthesize compounds with improved stereoselectivities. − Typically, the 1,4-Michael additions with proline as organocatalyst afford modest enantioselectivity; surprisingly though, homoproline is found to be ineffective. , Both proline and homoproline are bipolar molecules; the reactions usually require polar solvents like DMSO or alcohol because of their insoluble nature. The oxadiazolone ring is frequently employed as a bioisostere for a carboxylic acid for having similar p K a .…”

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confidence: 99%

Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction

et al. 2018

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Pyrrolidine-oxadiazolone based organocatalysts are envisaged, synthesized, and utilized for asymmetric Michael reactions. Results of the investigations suggest that some of the catalysts are indeed efficient for stereoselective 1,4-conjugated Michael additions (dr: >97:3, ee up to 99%) in high chemical yields (up to 97%) often in short reaction time. As an extension, one enantiopure Michael adduct has been utilized to synthesize optically active octahydroindole.

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confidence: 99%

Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction

et al. 2018

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“…Xu used in the same reaction as the catalyst also chiral pyrrolidine-pyridine based catalysts [110]. The best results were achieved with derivative C69 under solvent-free conditions (12 h, 99%, d.r.…”

Section: Michael Additions In Ionic Liquidsmentioning

confidence: 96%

Organocatalytic Reactions Under Unusual Conditions

Tomá¹,

Šebesta²,

Mečiarová

2011

COC

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Organocatalyzed reactions can often be advantageously performed in non-traditional reaction media. Use of ionic liquids, water or brine often leads to improved yields and selectivities of organocatalytic transformations. In terms of energy source, organocatalyzed reactions can be significantly accelerated by microwave irradiation, ultrasound or high pressure. Reactions without solvent and performed in ball mills are also reviewed.

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“…d and l forms of proline are inexpensive; besides this, proline has two functional groups, a carboxylic acid and an amine [thus, the reactions usually require polar solvents such as dimethyl sulfoxide (DMSO) or alcohol due to their insoluble nature], and plays a significant role in bi-functional asymmetric catalysis, which has become a successful strategy for facilitating chemical transformations similar to enzymatic catalysis. Thus, proline and its derivatives, to construct stereocenters in organic compounds with better selectivities, are one of the major milestones in the field of organocatalysis. − …”

Section: Introductionmentioning

confidence: 99%

Asymmetric 1,4-Michael Addition in Aqueous Medium Using Hydrophobic Chiral Organocatalysts

et al. 2021

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Organic transformations exclusively in water as an environmentally friendly and safe medium have drawn significant interest in the recent years. Moreover, transition metal-free synthesis of enantiopure molecules in water will have a great deal of attention as the system will mimic the natural enzymatic reactions. In this work, a new set of proline-derived hydrophobic organocatalysts have been synthesized and utilized for asymmetric Michael reactions in water as the sole reaction medium. Among the various catalysts screened, the catalyst 1 is indeed efficient for stereoselective 1,4-conjugated Michael additions (dr: >97:3, ee up to >99.9%) resulting in high chemical yields (up to 95%) in a very short reaction time (1 h) at room temperature. This methodology provides a robust, green, and convenient protocol and can thus be an important addition to the arsenal of the asymmetric Michael addition reaction. Upon successful implementation, the present strategy also led to the formation of an optically active octahydroindole, the key component found in many natural products.

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Simple Chiral Pyrrolidine–Pyridine‐Based Catalysts for Highly Enantioselective Michael Addition to Nitro Olefins

Cited by 48 publications

References 56 publications

Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction

Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction

Organocatalytic Reactions Under Unusual Conditions

Asymmetric 1,4-Michael Addition in Aqueous Medium Using Hydrophobic Chiral Organocatalysts

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