Enantioselective Synthesis of 2,3-Disubstituted Succinic Acids by Oxidative Homocoupling of Optically Active 3-Acyl-2-oxazolidones

Kise, Naoki; Tokioka, Kyohei; Aoyama, Yasunori; Matsumura, Yoshihiro

doi:10.1021/jo00110a003

Cited by 73 publications

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“…The concise enantioselective synthesis of hinokinin (see Figure 2), for example, was achieved through the oxidative dimerization of the appropriate Evans oxazolidinone. [16] Application of such approaches to the synthesis of unsymmetrical lignans remained elusive, however, until the contributions of Baran and co-workers. Using their oxidative cross-coupling methodology they were able to conduct an efficient synthesis of enantioenriched bursehernin (91, Scheme 10).…”

Section: Burseherninmentioning

confidence: 99%

“…[15] Notably, the groups of both Kise and Helmchen developed useful strategies for the stereocontrolled enantioselective synthesis of several lignans, such as ent-hinokinin (6), through the oxidative dimerization of Evans oxazolidinones. [16] In addition to natural product synthesis, Paquette and co-workers made use of Despite the body of literature pertaining to oxidative enolate coupling that appeared in the last century, it remained a relatively underinvestigated research area. In terms of methodology development, cross-coupling with equal stoichiometry of reacting partners remained a significant challenge, and systems that enabled uniformly high levels of diastereocontrol were underexplored.…”

Section: Introductionmentioning

confidence: 99%

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Oxidative Coupling of Enolates, Enol Silanes, and Enamines: Methods and Natural Product Synthesis

2012

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The oxidative coupling of enolates, enol silanes, and enamines provides a direct method for the construction of useful 1,4-dicarbonyl synthons. Despite being first reported in 1935, with subsequent important advances beginning in the 1970’s, the development of this powerful reaction into a reliable methodology was somewhat limited. In recent years, there have been a number of reports from several research groups demonstrating advances in several neglected areas of oxidative coupling. This microreview summarizes these new advances in methodology and provides an overview of recent natural product syntheses that showcase the power of these transformations.

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Section: Burseherninmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oxidative Coupling of Enolates, Enol Silanes, and Enamines: Methods and Natural Product Synthesis

2012

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“…882w. 'H-NMR (300 MHz, CDCI,): 1.02 (s, I-Bu); 1.40 (d,J = 6.9,Me(2)); 1.46 (s, Me-C(5)); 1.49 (s, 1.50,1.56 (23,, rotamers); 4.00 (y. J = 6.9, H-C(1')); 4.86, 5.06 (2s, H-C(2), rotamers). ',C-NMR (75 MHz, CDCI,): 14.08 (Me); 23.24,23.38 (Me,rotamers) curboxylute (20).…”

Section: 'S)-2-( Tert-butyij-55-dimethyl-3-(z'-methylpent-4'-enoyl)-mentioning

confidence: 99%

Synthesis and First Applications of a New Chiral Auxiliary (tert‐butyl 2‐(tert‐butyl)‐5,5‐dimethyl‐4‐oxoimidazolidine‐1‐carboxylate)

Studer

Hintermann

Seebàch³

1995

Helvetica Chimica Acta

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Both enantiomers of teut-butyl 2-(tert-butyl)-5,5-dimethyl-4-oxoimidazolidine-1 -carboxylate (1 1 ; Bbdmoic) were prepared from L-alanine (Schemes I and 2). The parent heterocycle, 2-fert-butyl-5,5-dimethylimidazolidin-4-one (1 2; from 2-aminoisobutyramide, H-Aib-NH,, and pivalaldehyde) was also available in both enantiomeric forms by resolution with 0.0'-dibenzoyltartaric acid. The compound ( R ) -or (S)-11 was used as an auxiliary, but also as a chiral Aib building block in a dipeptide synthesis. The 3-propanoyl derivative 13 of (R)-11 was used for the preparation of enantiomerically pure 2-methyl-3-phenylpropanoic acid (enantiomer ratio (ex.) 99.5:0.5), by benzylation of the Zn-enolate (+ 14; Scheme 3 ) . Oxidative coupling of the bis-enolate derived from heptanedioic acid and (S)-11 (+23) and methanolysis of the auxiliary gave dimethyl trans-cyclopentane-l,2-dicarboxylate (26) with an e.r. of 93 :7 (Scheme 5, Fig. 5). The 3-(Boc-Gly)-Bbdmoic derivative 29 was doubly deprotonated and, after addition of ZnBr, alkylated with alkyl, benzyl, or allyl halides to give the higher amino-acid derivatives with excellent selectivities (e.r. > 99.5:0.5, Schemes 6 and 7). Michael additions of cuprates to [(E)-MeCH=CHCO]-Bbdmoic 36 occurred in high yields, but high diastereoselectivities were only observed with aryl cuprates (diastereoisomer ratio (d,r.) 99:l for R = Ph, Scheme 8). Finally, 3-(Boc-CH2)-Bbdmoic 17 was alkylated through the ester Li-enolate with primary and secondary alkyl, allyl, and benzyl halides with diastereoselectivities (ds) ranging from 91 to 98%, giving acetals of Boc-Aib-Xxx-O(r-Bu) dipeptides (Scheme 4). The effectiveness of Bbdmoic is compared with that of other chiral auxiliaries previously used for the same types of transformations.1. Introduction. -Since the first reports of chiral-auxiliary-induced stereoselective reactions in the early 20th century by McKenzie [l], many 'chiral inductors' have been developed and successfully applied in asymmetric synthesis. The chemistry of auxiliarycontrolled stereoselective reactions (covalently bound) has been reviewed by several authors [2-81. Normally, these chiral auxiliaries are derived from natural sources such as amino acids [2] [3], carbohydrates [4] [5], terpenes [6], and steroids [9]. Synthetic auxiliaries that can be recovered after a reaction have also been described [7] [8] [lo-131. In Fig. I , a collection of successfully applied chiral auxiliaries is presented.During the last ten years, we have developed various chiral building blocks, based on five-membered heterocycles, oxazolidinones [28], and imidazolidinones [29], for the preparation of enantiomerically pure natural and unnatural amino acids. In the present paper, we report the synthesis and some applications of a new chiral auxiliary which is based on the imidazolidinones.

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“…This example shows that trifluoromethyl iodide can be used as reagent for the oxidative coupling besides the well known reagents like iodine 3i,6,7 , Cu(II)-salts 3p,q,6,7 , Ce(IV)-salts 3j and TiCl 4 3b, 6 . Subsequent ozonolysis of the crude product 3a and purification by flash chromatography gave the 2,3-disubstituted 1,4diketone 4a with an overall yield of 11%, a d/l:meso ratio of 67:33 and an enantiomeric excess of 83%.…”

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confidence: 93%

Diastereo- and Enantioselective Synthesis ofsyn-2,3-Disubstituted 1,4-DiketonesviaOxidative Coupling of Metalated Hydrazones

Enders¹,

Müller²,

Klein³

1998

Synlett

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An efficient diastereo-and enantioselective synthesis of syn-2,3-disubstituted 1,4-diketones 4 is described. Key step of the procedure is the oxidative coupling of the metalated SAMP/RAMP-hydrazones 2 with iodine, followed by oxidative cleavage of the dimerized bishydrazones 3 with ozone and subsequent separation of the minor meso-isomer by chromatography. The d,l-isomers of the title 1,4diketones 4 are obtained in good overall yields (20 -64%) and high diastereo-and enantiomeric excesses (de ≥ 98%, ee = 80 − ≥95%).1,4-Diketones constitute an important class of compounds 1 , for instance as precursors of cyclopentanoids and five-membered heteroaromatics 2 . Although numerous synthetic routes to 1,4-diketones are known 3 , there are only a few asymmetric syntheses of the title compounds published so far 4 , and the direct approach via auxiliary controlled oxidative coupling has very recently been reported only for the related 1,4dicarboxylic acid derivatives 5-7 . The latter reports prompt us to disclose our own early results 8 on the asymmetric synthesis of 1,4-diketones via oxidative coupling of metalated SAMP/RAMP-hydrazones with iodine and subsequent removal of the auxiliary by ozonolysis.

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Enantioselective Synthesis of 2,3-Disubstituted Succinic Acids by Oxidative Homocoupling of Optically Active 3-Acyl-2-oxazolidones

Cited by 73 publications

References 0 publications

Oxidative Coupling of Enolates, Enol Silanes, and Enamines: Methods and Natural Product Synthesis

Oxidative Coupling of Enolates, Enol Silanes, and Enamines: Methods and Natural Product Synthesis

Synthesis and First Applications of a New Chiral Auxiliary (tert‐butyl 2‐(tert‐butyl)‐5,5‐dimethyl‐4‐oxoimidazolidine‐1‐carboxylate)

Diastereo- and Enantioselective Synthesis ofsyn-2,3-Disubstituted 1,4-DiketonesviaOxidative Coupling of Metalated Hydrazones

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