Enantioselective Synthesis of Oasomycin A, Part I: Synthesis of the C1–C12 and C13–C28 Subunits

Evans, David A.; Nagorny, Pavel; McRae, Kenneth J.; Reynolds, Dominic J.; Sonntag, Louis Sebastian; Vounatsos, Filisaty; Xu, Risheng

doi:10.1002/anie.200603653

Cited by 21 publications

(4 citation statements)

References 25 publications

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“…Starting from Chan diene 447 , reaction with bidentate benzyloxyacetaldehyde ( 448 ) in the presence of Cu(II) complex ent - 398 followed by acidic treatment furnished ( R )-configured keto ester 449 in good yield and high enantiomeric excess (95% ee). Diastereoselective reduction of the ketone moiety and ester-to-aldehyde transformation provided the requisite fragment 450 , which was utilized in the successful total synthesis of the challenging 42-membered macrolide target 451 . , …”

Section: Vinylogous Aldol Reactionsmentioning

confidence: 99%

The Vinylogous Aldol and Related Addition Reactions: Ten Years of Progress

et al. 2011

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Section: Vinylogous Aldol Reactionsmentioning

confidence: 99%

The Vinylogous Aldol and Related Addition Reactions: Ten Years of Progress

et al. 2011

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“…Chiral aldehydes containing a-stereocentres are widely employed as versatile chiral building blocks 1 for the asymmetric synthesis of complex natural products 2 and drug like molecules, 3 which has resulted in a wide range of methodology being developed for their asymmetric synthesis. They may be prepared directly via reduction of chiral amides, 4 Weinreb amides, 5 N-acyl-5,5-dimethyl-oxazolidin-2-ones, 6 N-acyl-thiazolidine-2-thiones, 7 N-acyl-sultams, 8 thioesters, 9 and oxazolines, 10 although the yield of chiral aldehyde produced may be low due to competing over-reduction to its corresponding alcohol. Enantiopure a-substituted aldehydes may also be prepared via oxidation of their corresponding chiral primary alcohols, 11 although care must be taken to ensure that racemisation of their a-stereocentres does not occur.…”

Section: Introductionmentioning

confidence: 99%

A temporary stereocentre approach for the asymmetric synthesis of chiral cyclopropane-carboxaldehydes

et al. 2009

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A novel way of combining chiral auxiliaries and substrate directable reactions is described that employs a three-step sequence of aldol/cyclopropanation/retro-aldol reactions for the asymmetric synthesis of enantiopure cyclopropane-carboxaldehydes. In the first step, reaction of the boron enolate of (S)-N-propionyl-5,5-dimethyl-oxazolidin-2-one with a series of alpha,beta-unsaturated aldehydes affords their corresponding syn-aldol products in high de. In the second step, directed cyclopropanation of the alkene functionalities of these syn-aldols occurs under the stereodirecting effect of their 'temporary'beta-hydroxyl stereocentres to give a series of cyclopropyl-aldols in high de. Finally, retro-aldol cleavage of the lithium alkoxide of these cyclopropyl-aldols results in destruction of their temporary beta-hydroxy stereocentres to afford the parent chiral auxiliary and chiral cyclopropane-carboxaldehydes in >95% ee. The potential of this methodology has been demonstrated for the asymmetric synthesis of the cyclopropane containing natural product cascarillic acid in good yield.

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“…Eventually, we pursued the assembly of the ( E , Z )-diene moiety through a Suzuki cross-coupling strategy. Thus, the chiral auxiliary of 12 was removed through the formation of a thioester (EtSLi, 83% yield), which was reduced by DIBALH to provide the corresponding aldehyde . The following Stork–Zhao olefination provided cis -vinyl iodide 13 as a 14:1 mixture of Z : E isomers (68% yield, two steps) .…”

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confidence: 99%