1,3-syn diastereoselective reduction of β-hydroxyketones with diisobutylaluminum hydride and tributyltin hydride

Kiyooka, Syun‐ichi; KURODA, H.; Shimasaki, Yayoi

doi:10.1016/s0040-4039(00)84703-6

Cited by 138 publications

(54 citation statements)

References 12 publications

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“…Diastereoselective reduction (DIBALH, THF) then afforded a syn-diol (92%, !20:1 d.s. ), 33 which was protected as its corresponding PMP acetal (20). As expected, regioselective reductive cross-coupling of internal alkyne 5 with terminal alkyne 20 provided a functionalized 1,3-diene in 66% isolated yield (r.r.…”

Section: Revised Routementioning

confidence: 99%

A formal total synthesis of dictyostatin

Shimp

Micalizio

2009

Tetrahedron

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Section: Revised Routementioning

confidence: 99%

A formal total synthesis of dictyostatin

Shimp

Micalizio

2009

Tetrahedron

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“…When 14 was converted into a tin(II) (Z)-enolate with Sn(OTf) 2 /Hünig's base (iPr 2 NEt) at Ϫ78°C, and 15 then gradually added dropwise, the synselective aldol reaction proceeded smoothly to give the adduct, with a selectivity of more than 20:1. This β-hydroxy ketone was immediately subjected to a stereoselective reduction with diisobutylaluminium hydride (DIBAH) [11] to give diol 13 with all the expected syn configurations. The stereochemistry of 13 was confirmed by conversion into acetonide 13Ј and by its NMR spectrum [J H5-H6 (ax-eq) ϭ 1.8 Hz, J H6-H7 (eq-ax) Ͻ 1.0 Hz].…”

Section: Synthesis Ofmentioning

confidence: 99%

Stereoselective Synthesis of the C(1)−C(12) Fragments of Tedanolides − Application of a syn-Selective Tin(II)-Mediated Aldol Reaction and a Convertible Methoxybenzyl Protecting Group

Matsui¹,

Zheng²,

Kusaka³

et al. 2001

Eur. J. Org. Chem.

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“…95:5) was achieved in the reduction of b-hydroxyketone 12 with DIBAL-H at À78 8C (Scheme 3). [12] The diastereomeric ratio was determined by GC/MS analysis of acetonide 14.…”

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confidence: 99%

Total Synthesis and Structural Elucidation of (−)‐Delactonmycin

Corrêa

Pilli

2003

Angew Chem Int Ed

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Dedicated to Professor Albert J. Kascheres on the occasion of his 60th birthdayIn recent years, a number of highly cytotoxic polyketides with similar chemical structures, including the leptomycins, kazusamycins, anguinomycins, and leptolstatins, were isolated as secondary metabolites from Streptomyces strains.[1] In 1997, Wang et al. identified two novel polyketides, named delactonmycin and dilactonmycin, in the extracts from Streptomyces strain A92-308902 with very potent inhibitory activity of the nucleo-cytoplasmic translocation of the HIV-1 regulatory protein Rev.[2] The planar structure of delactonmycin was established by spectroscopic methods, but its relative as well as its absolute configuration remained unknown. In our synthetic studies towards the elucidation of the relative configuration of delactonmycin (1), we were led to presume that it is the same as that of leptomycin B and callystatin Aa structurally related polyketide isolated from the marine sponge Callyspongia truncata [3] -whose relative and absolute configurations were established by spectroscopic methods and total synthesis. [4,5] Our interest in the synthesis of delactonmycin stemmed from its greater structural simplicity relative to that of other members of this class, which renders it an interesting model compound for structure-activity studies.[6] Additionally, the implementation of a successful approach to 1 would pave the way to the total synthesis of other polyketides whose structures have not yet been confirmed by total synthesis. Herein, we disclose our approach and results toward the first total synthesis and structural elucidation of (À)-delactonmycin (1, Scheme 1).The installation of the C4ÀC5 bond through E-selective Wittig olefination between aldehyde 2 and phosphonium bromide 3 was left to a late stage of the synthesis in our retrosynthetic analysis. In turn, 3 could be obtained from a Wittig olefination of aldehyde 4 with ethyl triphenylphosphoranylidene propionate. It was envisaged that aldehyde 4 could be prepared from the syn aldol adduct obtained from the reaction between ethyl ketone 5 and g,d-unsaturated aldehyde 6. The fragments 2, 5, and 6 are available from the methyl (R)-and (S)-3-hydroxy-2-methylpropionates, which we have already used in the total synthesis of the aglycon of the macrolide antibiotic 10-deoxymethymycin. [7] Aldehyde 6 was readily obtained through the sequence shown in Scheme 2. A palladium-catalyzed cross-coupling reaction between the chiral zinc homoenolate 8 [8,9] and cis-2-bromo-2-butene (both commercially available) led to the formation of 11, which was carefully reduced with diisobutylaluminum hydride at À90 8C to afford 6 in 86 % overall yield. Ketone 5 was prepared as described by Paterson et al. [10] in three steps and 57 % overall yield. Conversion of (R)-7 into the Weinreb amide 9 was followed by protection as its p-methoxybenzyl ether 10. Subsequent addition of ethyl magnesium bromide provided ethyl ketone 5. Treatment of 5 with stannous triflate and Et 3 N at À78 8C in CH 2 Cl 2 gene...

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1,3-syn diastereoselective reduction of β-hydroxyketones with diisobutylaluminum hydride and tributyltin hydride

Cited by 138 publications

References 12 publications

A formal total synthesis of dictyostatin

A formal total synthesis of dictyostatin

Stereoselective Synthesis of the C(1)−C(12) Fragments of Tedanolides − Application of a syn-Selective Tin(II)-Mediated Aldol Reaction and a Convertible Methoxybenzyl Protecting Group

Total Synthesis and Structural Elucidation of (−)‐Delactonmycin

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