Asymmetric synthesis of the C1–C6 portion of the psymberin using an Evans chiral auxiliary

Pal, Ashutosh; Peng, Zhenghong; Schuber, Paul T.; Prasad, Basvoju A. Bhanu; Bornmann, William G.

doi:10.1016/j.tetlet.2013.05.153

Cited by 5 publications

(3 citation statements)

References 21 publications

(23 reference statements)

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“…We surveyed the last‐mentioned oxazolidinone 6 , three achiral analogs ( 5 , 7 , and 10 ), and two chiral analogs ( 8 , 9 ) in aldol additions to hydrocinnamic aldehyde (Table ). The dibutylboron enolates of these oxazolidinones 5 – 10 were formed with Bu 2 BOTf and NEt 3 in dichloromethane at –40 °C .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of trans‐Configured Enol Ethers by a Sequence of syn‐Selective Glycolate Aldol Addition, Hydrolysis, and Grob Fragmentation

Engesser

Brückner

2017

Eur J Org Chem

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A trans‐selective access to enol ethers with a disubstituted C=C bond was developed. It consists of a diastereoselective glycolate aldol addition, a hydrolysis, and a Grob fragmentation. Aldol additions of N‐[(benzyloxy)acetyl]oxazolidinones furnished syn‐aldols selectively. Hydrolytic removal of the auxiliaries gave α‐benzyloxy‐β‐hydroxycarboxylic acids. Exposure to DMF dineopentylacetal induced Grob fragmentations, which delivered trans‐configured enol ethers. Applying our 3‐step sequence in a bidirectional synthesis led to bis(enol ethers) trans,trans‐selectively, i.e., to a motif rarely encountered in the literature. A modified precursor synthesis allowed for the first time to access both the E‐ and the Z‐isomer of an enol ether with a trisubstituted C=C bond stereoselectively using a Grob fragmentation route. The Ar–Br and C≡C–SiMe2tBu motifs of appropriate enol ethers engaged in follow‐up reactions via organometallics. These provided more elaborated enol ethers.

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Section: Resultsmentioning

confidence: 99%

Synthesis of trans‐Configured Enol Ethers by a Sequence of syn‐Selective Glycolate Aldol Addition, Hydrolysis, and Grob Fragmentation

Engesser

Brückner

2017

Eur J Org Chem

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“…149 anti-Configured aldols 101 result from N-glycolyloxazolidinones 100 via Sn(II) enolates (Table 18). 99,[150][151][152][153][154][155] Diastereocontrol is moderate in the presence of TMEDA (ratio major aldol/all other aldols = 73:27 to 83:17) and absent otherwise. 155 An aldehyde with NMeCbz as an α-substituent behaved similarly.…”

Section: Syn Thesismentioning

confidence: 99%

Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives

Engesser¹,

Brückner²

2019

Synthesis

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This review gives a comprehensive overview of aldol additions of glycolic acid derivatives to achiral aldehydes and acetals affording α,β-dihydroxycarboxylic acids or derivatives thereof. The focus is on simple diastereoselectivity. A selection of related aldol additions is also presented: aldol additions of glycolic acid derivatives to ketones with two different substituents and aldol additions of α-substituted glycolic acid derivatives.1 Introduction1.1 Organization of this Review1.2 Outside the Scope of this Review: Aldol Additions Giving α,β-Dihydroxyaldehydes and α,β-Dihydroxyketones Diastereoselectively1.3 Non-Aldol Routes to Diastereomerically Pure α,β-Dihydroxycarboxylic Acid Derivatives2 Aldol Additions of Glycolic Acid (Derivative) Enolates to Aldehydes2.1 Aldol Additions of Glycolate Enolates (‘Glycolic Acid Dianions’)2.2 Aldol Additions of Glycolic Ester Enolates2.3 Aldol Additions of Glycolic Thioester Enolates2.4 Aldol Additions of Glycolimide Enolates2.5 Aldol Additions of Glycolamide Enolates2.6 Mukaiyama Aldol Additions of Silyl Ketene Acetals of Glycolic Esters and Thioesters2.7 Aldol Additions of Glycoloyl Chlorides via Acyl Ammonium Enolates3 Aldol-Providing Substitutions of Glycolimide Enolates in Acetals4 Additions Related to Aldol Additions of Glycolic Acid Derivative Enolates to Aldehydes4.1 Selected Simply Diastereoselective Aldol Additions of Enolates of Glycolic Acid Derivatives to Ketones with Two Different Substituents4.2 Simply Diastereoselective Aldol Additions of Enolates of Glycolic Acid Derivatives with a Methyl Substituent at C-α (Lactic Acid Derivatives)5 Conclusion

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“…In 2005, the first total synthesis of (+)-irciniastatin A ( 1 ) was accomplished by De Brabander and co-workers, who established the absolute configuration of (+)- 1 and demonstrated that (+)-irciniastatin A and psymberin possess identical structures. After this pioneering synthesis, 7 total syntheses including the synthesis by our laboratory, 2 formal syntheses, and 10 synthetic studies have been reported.…”

Section: Introductionmentioning

confidence: 99%

Total Synthesis and Biological Evaluation of Irciniastatin A (a.k.a. Psymberin) and Irciniastatin B

et al. 2015

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Irciniastatin A (a.k.a. psymberin) and irciniastatin B are members of the pederin natural product family, which have potent antitumor activity and structural complexity. Herein, we describe a full account of our total synthesis of (+)-irciniastatin A and (-)-irciniastatin B. Our synthesis features the highly regioselective Eu(OTf)3-catalyzed, DTBMP-assisted epoxide ring opening reaction with MeOH, which enabled a concise synthesis of the C1-C6 fragment, extensive use of AZADO (2-azaadamantane N-oxyl) and its related nitroxyl radical/oxoammonium salt-catalyzed alcohol oxidation throughout the synthesis, and a late-stage assembly of C1-C6, C8-C16, and C17-C25 fragments. In addition, for the synthesis of (-)-irciniastatin B, we achieved the C11-selective control of the oxidation stage via regioselective deprotection and AZADO-catalyzed alcohol oxidation. The synthetic irciniastatins showed high levels of cytotoxic activity against mammalian cells. Furthermore, chemical footprinting experiments using synthetic compounds revealed that the binding site of irciniastatins is the E-site of the ribosome.

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Asymmetric synthesis of the C1–C6 portion of the psymberin using an Evans chiral auxiliary

Cited by 5 publications

References 21 publications

Synthesis of trans‐Configured Enol Ethers by a Sequence of syn‐Selective Glycolate Aldol Addition, Hydrolysis, and Grob Fragmentation

Synthesis of trans‐Configured Enol Ethers by a Sequence of syn‐Selective Glycolate Aldol Addition, Hydrolysis, and Grob Fragmentation

Stereoselective Aldol Additions of Glycolic Acid and Its Derivatives

Total Synthesis and Biological Evaluation of Irciniastatin A (a.k.a. Psymberin) and Irciniastatin B

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