Aminocatalytic remote functionalization strategies

Jiang, Hao; Albrecht, Łukasz; Jørgensen, Karl Anker

doi:10.1039/c3sc50405k

Cited by 241 publications

(54 citation statements)

References 64 publications

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“…The success of this novel catalytic mode relies on the rational design of the polyunsaturated ketone substrates, which contain an appropriately positioned d,e-C=C bond to induce the in situ generation of HOMOraised linear trienamine species. In contrast to early examples of trienamine catalysis, [5,6] the current cycloaddition exhibits exclusive remote d,e-regioselectivity, and excellent catalytic efficacy and stereocontrol were observed for the reactions of a variety of substrates with substantial scope. Moreover, an aza-Diels-Alder reaction/Michael addition process was developed by introducing a functional group to the 2,5-dienone substrates.…”

Section: C1mentioning

confidence: 92%

Trienamines Derived from Interrupted Cyclic 2,5‐Dienones: Remote δ,ε‐CC Bond Activation for Asymmetric Inverse‐Electron‐Demand Aza‐Diels–Alder Reaction

Feng

Zhou

et al. 2013

Angewandte Chemie

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A special challenge in the field of asymmetric catalysis is the realization of remote stereocontrol.[1] The problem can be extended to remote sites which must be activated to ensure better reactivity. While most early examples of remote asymmetric inductions rely on enzyme catalysis or intramolecular relay of chiral information through the substrate, [2] current studies have demonstrated that chiral catalysts can facilitate enantioselectivity in variety of reactions.[3] In particular, our group and the group of Jørgensen found that the well-established enamine chemistry of saturated carbonyl compounds could be expanded to polyconjugated 2,4-dienals based on the principle of vinylogy, [4] thus leading to the remote e-site activation and still allowing highly stereoselective cycloadditions at b,e-sites of in situ formed linear trienamine intermediates.[5] Moreover, such an activation mode was successfully applied to 2,4-dienone analogues. Unfortunately, it was not possible to utilize 2,4-dienones with an enolizable a'-alkyl substitution because the cross-conjugated trienamine species were preferably generated. [6] In fact, we also found that the cyclic 2,4-dienone 1 would predominantly generate the cross-conjugated trienamine I, catalyzed by a primary amine, and then react with a dienophile by a a',b-regioselective [4+2] annulation pathway (Scheme 1). [7] To overcome the inherent preference for the formation of cross-conjugated trienamines from 2,4-dienones bearing an enolizable a'-alkyl group, we envisaged that an appropriately positioned d,e-C=C bond, as shown for the interrupted 3-allyl cyclohexen-2-one 2 a (Scheme 1), would induce the generation of the desired polyconjugated linear trienamine II, rather than the dienamine [8] III which has a higher energy.[9] Thus, the electron-donating effects of the amine could be transmitted through the conjugated p system, and raise the HOMO energy of the remote d,e-C=C group to participate in asymmetric reactions.Based on the above considerations, we initially investigated the reaction of the 2,5-dienone 2 a and the 1-azadiene 3 a, containing a 1,2-benzoisothiazole-1,1-dioxide moiety, [10] in the presence of 9-amino-9-deoxyepiquinidine (C1) and benzoic acid (A1).[11] To our gratification, the reaction proceeded smoothly in toluene at 35 8C, and the inverse-electrondemand aza-Diels-Alder cycloaddition product 4 a was isolated in 63 % yield with exclusive d,e-regioselectivity.

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Section: C1mentioning

confidence: 92%

Trienamines Derived from Interrupted Cyclic 2,5‐Dienones: Remote δ,ε‐CC Bond Activation for Asymmetric Inverse‐Electron‐Demand Aza‐Diels–Alder Reaction

Feng

Zhou

et al. 2013

Angewandte Chemie

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“…[36] Utilizing the vinylogous reactivity in amino catalysis, [37a] Melchiorre developed a vinylogous organocatalytic triple cascade reaction and applied this reaction for forming six stereocenters in complex spiro-oxindolic cyclohexanes.…”

Section: A C H T U N G T R E N N U N G Clization Reaction Sequence Ofmentioning

confidence: 99%

Catalytic Asymmetric Synthesis of Chiral Benzofuranones

Cheng

2014

Adv Synth Catal

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The chiral benzofuranone structural motif is a prominent feature in many natural products, which exhibit a broad range of biological and pharmaceutical activities. In the past few years, a survey of chiral benzofuranone derivatives based on asymmetric catalysis reveals an increasing number of papers, which reflects the latest achievements to facilitate the synthesis of sufficient quantities of related compounds as potential medicinal agents and biological probes. Recent advances in this area are summarized and classified according to the structure of the starting substrate.

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“…Recently, dienamine and trienamine catalysis has become available for remote functionalizations of α,β-unsaturated compounds. [6][7][8] In 2006 Jørgensen disclosed a dienamine concept by showing the direct γ-functionalization of α,β-unsaturated aldehydes. 9 Pentenal reacts with diethyl azodicarboxylate (DEAD) in the presence of 2-[bis(3,5)-bistrifluoromethylphenyl)-trimethylsilanyloxymethyl]pyrrolidyne (silyl protected diarylprolinol) and benzoic acid furnishing the γ-amino substituted product in 56% yield.…”

Section: Introductionmentioning

confidence: 99%