Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization

Bocknack, Brian M.; Wang, Long Cheng; Krische, Michael J.

doi:10.1073/pnas.0307120101

Cited by 131 publications

(50 citation statements)

References 56 publications

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“…For example, the reaction of keto-enone 164a (n = 1) with phenylboronic acid in the presence of a rhodium/(R)-binap catalyst gave the five-membered ring aldol product 165am exclusively, in 88% chemical yield and 94% ee. This method was elegantly applied to the desymmetrization of diketoenones 166, which resulted in the stereoselective formation of bicycle 167 with four contiguous stereogenic centers, including a quaternary center (Scheme 1.63) [213].…”

Section: Rh-catalyzed Tandem Processesmentioning

confidence: 99%

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

Berthon

Hayashi

2010

Catalytic Asymmetric Conjugate Reactions

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Section: Rh-catalyzed Tandem Processesmentioning

confidence: 99%

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

Berthon

Hayashi

2010

Catalytic Asymmetric Conjugate Reactions

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“…Finally,preliminary efforts at developing enantioselective reactions were conducted (Table 3). [23] Only modest results were obtained with chiral diene ligands [24] (see Supporting Information), while no reaction occurred when chiral bisphosphines were used. However, the reaction of 1a with 3,5dimethylphenylboronic acid (1.3 equiv) in the presence of [{Rh(C 2 H 4 ) 2 Cl} 2 ]( 2.5 mol %), the sulfur-alkene L1 [25] (5.0 mol %), and KF (1.5 equiv) in TBME/tBuCN/MeOH (40:5:1) gave (+ +)-2aa [17] in 61 %y ield and 91 % ee (entry 1).…”

Section: Angewandte Chemiementioning

confidence: 99%

Arylative Intramolecular Allylation of Ketones with 1,3‐Enynes Enabled by Catalytic Alkenyl‐to‐Allyl 1,4‐Rhodium(I) Migration

et al. 2017

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Alkenyl-to-allyl 1,4-rhodium(I) migration enables the generation of nucleophilic allylrhodium(I) species by remote CÀHa ctivation. This new mode of reactivity was employed in the diastereoselective reaction of arylboron reagents with substrates containing a1 ,3-enyne tethered to ak etone,t og ive products containing three contiguous stereocenters.T he products can be obtained in high enantioselectivities using ac hiral sulfur-alkene ligand.CatalyticCÀHfunctionalizationshave revolutionized chemical synthesis by providing powerful new tools for bond construction.[1] However,acritical objective for the advancement of this field is its application to amore diverse range of transformations.N ucleophilic allylations [2] are important reactions that could benefit from C À Hf unctionalization principles.M ost typically,t hese processes have employed allylmetal(loid) reagents such as allyltin, allylboron, or allylsilicon compounds.[2] Theg eneration of nucleophilic allylmetal species by the activation of allylic C À Hb onds would bypass the need to prepare such reagents and potentially increase efficiencyb ys treamlining synthetic sequences.This strategy would also be avaluable complement to nucleophilic allylations involving migratory insertions of allenes, [3,4] theu se of simple p-unsaturated compounds in hydrogenative or redox-triggered additions, [5,6] hetero-ene reactions, [7] and Prins reactions.[8]Although generating electrophilic allylmetal species by allylic CÀHa ctivation is well-known, [9,10] there is,t oo ur knowledge,l imited precedent for corresponding processes that provide nucleophilic allylmetals.[11] Very recently,t he groups of Schneider, [11a] Kanai, [11b] and Mita and Sato [11c] described the formation and trapping of nucleophilic allylmetal species from simple hydrocarbons.I nv iew of the nucleophilic character of allylrhodium(I) species, [4a, 12] we envisaged that activation of ar emote CÀHb ond by 1,4-rhodium(I) migration [12d, 13, 14] could also achieve this goal. Specifically,r hodium(I)-catalyzed reaction of an arylboron reagent with the alkyne of a1 ,3-enyne would provide the alkenylrhodium species A (Scheme 1). This intermediate could then undergo a1 ,4-rhodium(I) shift to the cis-allylic substituent to give the allylrhodium(I) species B,which could be trapped by an electrophile.This approach was expected to be challenging,given that there is only very limited precedent for rhodium(I) to migrate to C(sp 3 )c enters.[12d,14k,m] Nevertheless,t he generation of electrophilic allylrhodium(III) species by as imilar strategy in our rhodium(III)-catalyzed oxidative annulations of 1,3-enynes provided some encouragement.[10] Herein, we describe the implementation of this strategy in arylative intramolecular allylations of ketones to give stereochemically complex fused bicycles with high diastereoselectivities.P reliminary results of enantioselective reactions are also provided.This study began with the reaction of the enynone 1a with 3,5-dimethylphenyl pinacol boronate (1.3 equiv), [...

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“…In light of these results, Krische and coworkers explored the applicability of such methodology for the desymmetrization of prochiral diketones (73, R 2 = R 3 ), as well as for the kinetic resolution of racemic substrates (73, R 2 = R 3 ) using arylboronic acid 74 in the presence of catalytic amounts of (S)-BINAP (39) and the methoxy-bridged dimer [Rh(cod)(OMe)] 2 as precatalytic species (Scheme 8.16) [28]. The Rh-enolate generated on enone carbometallation effectively discriminates among four diastereotopic π-faces of the dione, providing products that embody four contiguous stereocenters, including two quaternary centers, with excellent levels of diastereoselectivity (>99 : 1 dr) and enantioselectivity (85-92% ee).…”

Section: Scheme 811mentioning

confidence: 99%