Recyclable Tertiary Amine Modified Diarylprolinol Ether as Aminocatalyst for the Sequential Asymmetric Synthesis of Functionalized Cyclohexanes and Chromenes

Shen, Hao; Yang, Ke‐Fang; Shi, Zi-Hui; Jiang, Jianxiong; Lai, Guoqiao; Xu, Li‐Wen

doi:10.1002/ejoc.201100613

Cited by 37 publications

(9 citation statements)

References 107 publications

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“…The functionalization of the vinylphosphonates under various reaction conditions provides access to versatile phosphorus-containing synthetic intermediates . Such transformations include the Michael addition reactions (aza-, sulfa-, and oxa-Michael addition reactions), Diels–Alder reaction, epoxidations, aminohydroxylation, dihydroxylation, aziridination, Heck reaction, ene reaction, and cross-metathesis reactions . In addition, vinylphosphonate derivatives have also shown significant biological activities: they have been extensively explored for anticancer, , antiviral, , and antibacterial applications .…”

Section: Introductionmentioning

confidence: 99%

Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon–Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates

et al. 2015

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An efficient and practical protocol for completely regioselective and highly stereoselective synthesis of vinyldiazaphosphonates from N-heterocyclic phosphine (NHP) and allenes via phospha-Michael/intramolecular nucleophilic substitution reaction has been developed. This transformation enabled the synthesis of valuable densely functionalized vinyldiazaphosphonates with a β-, γ-unsaturated ester moiety under mild reaction conditions. Synthetic utility of vinyldiazaphosphonates was demonstrated by a series of synthetic manipulations.

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Section: Introductionmentioning

confidence: 99%

Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon–Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates

et al. 2015

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“…In 2011, Xu and coworkers developed a novel tertiary amine‐modified diarylprolinol silyl ether 4 c , which, relatively, facilitated the oxa‐Michael‐adol reaction of 1 and 2 , resulting 2 H ‐flavenes with moderate to good enantioselectivities (Scheme ) . Although the steric difference between ( R )‐ 4 a and 4 c was subtle, the authors believed that the electronic effect of the tertiary amine groups of 4 c enhanced the enantioselective activity of the chiral seconary amine, leading to a better result.…”

Section: Asymmetric Synthesis Of 2h‐flavenesmentioning

confidence: 99%

Catalytic Asymmetric Syntheses of 2‐Aryl Chromenes

2019

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Chiral chromene motifs are important heterocycles in numerous natural products and bioactive molecules. Among them, flavenes, flavanes, and flavanones, which consist of the 2-aryl-chromene skeleton are observed most frequently. As subgroups of flavonoids, they often occur in various plants and show many biological activities, such as antitumor, antioxidant, antibacterial, anti-inflammatory, and anticoagulant properties. This Minireview summarizes recent reports on catalytic asymmetric synthesis of flavenes, flavanes, and flavanones. derivatives 1, giving the adduct 6. The subsequent intramolecular adol reaction and dehydration providing the desired product 3 (Scheme 2).Almost the same time, professor Córdova and coworkers presented the same domino reaction between 1 a and 2 catalyzed by 4 a, providing a series of 2H-flavenes in high yields and with 83-98% ees (Scheme 3). [5] Notably, by using 2nitrobenzoic acid as an additive, product 3 a could be obtained with 37% yield and 88% ee, comparing to 10% yield and 9% ee when adding no additives. More significantly, another additive, 4 Å molecular sieves, promoted the reaction significantly, increasing the product yield from 37% to 81% with no enantioselectivity erosion. The authors believed that the addition of an organic acid accelerated the adol condensation by activating the benzaldehyde. Also, the organic acid could stabilized the iminium intermediate, facilitating the oxa-Michael addition. The product 7 could be observed by NMR analysis, which gave an obvious evidence to the proposed reaction pathway (Scheme 2).By applying the similar approach, Wang and coworkers developed the asymmetric reaction of 1 and 2 catalyzed by organocatalyst 4 b. [6] Different from Córdova's condition, Wang found that Cl(CH 2 ) 2 Cl was the best solvent to provide the highest enantioselectivity. Lowering the reaction temperature improved ee with prolonged time for completion. The reaction had a broad scope and the functionalized 2H-flavenes were synthesized respectively high yields (53-98%) and with good to excellent levels of enantioselectivities (75-99% ee). However, the electronic nature of the α,β-unsaturated aldehydes 2 had a remarkable effect on the reactivities and ees that 2 bearing electron-withdrawing groups, such as nitro group, generally Scheme 2. Proposed mechanism of the organocatalytic asymmetric oxa-Michael addition/intramolecular adol reaction/dehydration cascade. Scheme 3. Direct organocatalytic asymmetric domino oxa-Michael/aldol condensations between 1 a and α, β-unsaturated aldehydes 2.

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“…Very recently, Xu et al [46] reported an improved protocol for the domino-oxa-Michael reaction of salicylaldehydes 1 with α,β-unsaturated aldehydes 2 employing tertiary amine-modified diarylpyrrolinol-TMS ether III as a water-soluble and recyclable organocatalyst with 4-chlorobenzoic acid as cocatalyst (Scheme 5) for the synthesis of 2 H -chromene derivatives 3 . The electronic effect of the tertiary amine group in the modified catalyst was believed to enhance the enantioselectivity of the chiral secondary amine.…”

Section: Reviewmentioning

confidence: 99%

Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines

Bhanja¹,

Jena²,

Nayak³

et al. 2012

Beilstein J. Org. Chem.

108

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SummaryEnantioselective organocatalysis has become a field of central importance within asymmetric chemical synthesis and appears to be efficient approach toward the construction of complex chiral molecules from simple achiral materials in one-pot transformations under mild conditions with high stereocontrol. This review addresses the most significant synthetic methods reported on chiral-amine-catalyzed tandem Michael conjugate addition of heteroatom-centered nucleophiles to α,β-unsaturated compounds followed by cyclization reactions for the enantioselective construction of functionalized chiral chromenes, thiochromenes and 1,2-dihydroquinolines in optically enriched forms found in a myriad of bioactive natural products and synthetic compounds.

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Recyclable Tertiary Amine Modified Diarylprolinol Ether as Aminocatalyst for the Sequential Asymmetric Synthesis of Functionalized Cyclohexanes and Chromenes

Cited by 37 publications

References 107 publications

Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon–Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates

Utility of Bifunctional N-Heterocyclic Phosphine (NHP)-Thioureas for Metal-Free Carbon–Phosphorus Bond Construction toward Regio- and Stereoselective Formation of Vinylphosphonates

Catalytic Asymmetric Syntheses of 2‐Aryl Chromenes

Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines

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