Total Syntheses of All Stereoisomers of Phenatic Acid B

Fernandes, Rodney A.; Chowdhury, Asim K.

doi:10.1021/jo901927w

Cited by 28 publications

(7 citation statements)

References 15 publications

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“…δ‐Functionalized γ‐lactones16 and γ‐alkylidenelactones17 represent two important types of scaffold which are frequently encountered as structural subunits in numerous biologically active products. Moreover, they are also important building blocks in natural product synthesis18 and drug synthesis 19…”

Section: Resultsmentioning

confidence: 99%

Mutually Complementary Metal‐ and Organocatalysis with Collective Synthesis: Asymmetric Conjugate Addition of 1,3‐Carbonyl Compounds to Nitroenynes and Further Reactions of the Products

Peng

et al. 2012

Adv Synth Catal

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The first metal-catalyzed 1,4-selective asymmetric addition of malonates to nitroenynes promoted by a simple chiral nickel(II)-diamine catalyst, was developed, facilitating a mild synthesis of a novel type of multifunctional chiral b-alkynyl acids bearing a nitro group. Based on this protocol, we have developed a practical and collective synthesis of a series of diverse functional molecules and building blocks including new types of chiral balkynyl-g-amino acids, b-functionalized chiral dketo-g-lactones, chiral g-alkylidenelactones, alkynylsubstituted pyrrole-3-carboxylic acid derivatives, tetrasubstituted furans and chiral b-alkynyl-g-lactams. Notably, we discovered two unusual tandem reactions leading to functionalized chiral 1,5-dicarbonyl compounds. In addition, by employing simple bifunctional organocatalysts, we have developed the first regio-, diastereo-and enantioselective conjugate addition of a-substituted b-keto esters to nitroenynes, which is poorly diastereoselective with chiral nickel(II)-diamine catalysts, providing a new entry to adjacent quaternary and tertiary stereocenters in one step. Based on this protocol, we have developed a concise asymmetric synthesis of conformationally constrained bicyclic g 2 -amino acids featuring an alkynyl side chain with an adjacent quaternary carbon stereocenter. The study described here demonstrates that the mutually complementary strategy of transition metal catalysis and organo-catalysis is a powerful and promising tool in catalytic asymmetric synthesis.

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Section: Resultsmentioning

confidence: 99%

Mutually Complementary Metal‐ and Organocatalysis with Collective Synthesis: Asymmetric Conjugate Addition of 1,3‐Carbonyl Compounds to Nitroenynes and Further Reactions of the Products

Peng

et al. 2012

Adv Synth Catal

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“…K03-0132, showed miconazole activity against Candida albicans. [110] Fernandes [111] The syntheses of xylobovide (204), [112] canadensolide (205), [113] sporothriolide (206), [114] and nor-canadensolide (207) by the preceding strategy were achieved by the Fernandes group. [115,116] As shown in Scheme 41, esters 196ac were transformed into allyl alcohols 197a-c by Sharpless asymmetric dihydroxylation.…”

Section: Applications In Synthesis Of Bioactive Molecules Natural Prmentioning

confidence: 99%

The Orthoester Johnson–Claisen Rearrangement in the Synthesis of Bioactive Molecules, Natural Products, and Synthetic Intermediates – Recent Advances

2013

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The orthoester Johnson–Claisen rearrangement, an important C–C bond forming reaction, has been used enormously in the past four decades in the synthesis of bioactive molecules, natural products, synthetic intermediates, analogues, and useful building blocks. The method has also featured in chemical modification of materials. This review covers developments in this rearrangement since 2003. Unlike many other forms of Claisen rearrangement, this reaction is generally a one‐pot, one‐step process. It is compatible with numerous functional groups, despite its use of acid catalysis, and offers chirality transfer to produce stereoselective products. The method also offers opportunities for rapid modifications to various functionalized compounds and building blocks for further synthetic exploration.

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“…Scheme 80). ROAc, 215 ROPiv, 92,226 ArOMe, 194,230,232,233,236,239,241,242 ArOBn, 131,242 ArOAllyl, 125 ArOMOM, 131,233 ArOAc, 232 methylenedioxy 131,242 ArOEOM, 241 and R 2 NBoc. 194,229,243 EOM: ethoxymethyl IBX is not soluble in many organic solvents and the typical oxidation takes place in DMSO at room temperature.…”

Section: Scheme 14mentioning

confidence: 99%

“…The oxidation of a primary alcohol has been described using 2 equivalents of IBX in EtOAc at reflux for 2 h. 172 In the synthesis of pluraflavin A by Danishefsky and his group, a secondary alcohol was also oxidized with 3.5 equivalents of IBX in EtOAc; the mixture was capped under argon and heated at 90 ºC for 6 h. 239 The preparation of a dialdehyde was achieved by the reaction of a bisbenzylic alcohol with 8.5 equivalents of IBX in EtOAc at reflux. 242 In the synthesis of all stereoisomers of phenatic acid B, the oxidation of a secondary alcohol was accomplished with 2 equivalents of IBX in refluxing EtOAc for 20 h. 236 In the formal synthesis of palmerolide A, primary alcohols were oxidized to the corresponding aldehydes using 1.3 to 1.5 equiv of IBX at reflux in EtOAc for 6 h. The crude aldehydes were used in Wittig or Horner-Wadsworth-Emmons reactions. 246 The oxidation of a primary allylic alcohol was reported using 2.5 equiv of IBX in refluxing EtOAc for 4 h during the total synthesis of (─)-englerin A.…”

mentioning

confidence: 99%