Chemical Conversion of Vibsanin C to Vibsanin E and Structure of 3-Hydroxyvibsanin E from <i>Viburnum awabuki</i>

Matsuda, Hiroyuki; Kagawa, Masami; Kodama, Masashi; Kawazu, Kazuyoshi

doi:10.1021/np980338v

Cited by 32 publications

(18 citation statements)

References 6 publications

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“…In the process of elucidating vibsane biochemical pathways Y. Fukuyama investigated the conversion of vibsanin C (2) to vibsanin E (3) [12] and found that conversion proceeded smoothly using borontrifluoride-diethyl ether, albeit in moderate yield (50 %) (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Towards the Total Synthesis of Vibsanin E, 15‐O‐Methylcyclovibsanin B,3‐Hydroxyvibsanin E, Furanovibsanin A, and 3‐O‐Methylfuranovibsanin A

et al. 2006

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Studies detailing synthetic approaches to a variety of biosynthetically related vibsanin‐type diterpenes (i.e. vibsanin E, 15‐O‐methylcyclovibsanin B, 3‐hydroxy‐vibsanin E, furanovibsanin A, and 3‐O‐methylfuranovibsanin A) are discussed. Biogenetically modelled approaches are coupled with an investigation of classical and modern six‐ to seven‐membered ring‐expansion protocols, which gain access to the central core of these natural products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Section: Introductionmentioning

confidence: 99%

Towards the Total Synthesis of Vibsanin E, 15‐O‐Methylcyclovibsanin B,3‐Hydroxyvibsanin E, Furanovibsanin A, and 3‐O‐Methylfuranovibsanin A

et al. 2006

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“…Besides, Fukuyama et al found plausible biosynthetic pathways to two other vibsanin-type diterpenes from 2 and 3, respectively. When vibsanin B (2) was treated with BF 3 · Et 2 O in CH 2 Cl 2 under anhydrous conditions at À 788 for a short period, vibsanin E (5), a tricyclic vibsanin-type diterpene was obtained, in 50% yield [23]. They also reported a plausible biosynthetic pathway leading to cyclovibsanins from vibsanin C (3), as shown in Scheme 3 [21].…”

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confidence: 99%

ChemInform Abstract: Chemical Constituents of Plants from the Genus Viburnum

Wang

2010

ChemInform

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“…In 1999 Fukuyama reported the isolation of 3-hydroxyvibsanin E ( 1 ) (Figure 1) from Viburnum awabuki 1 with an additional finding in Viburnum suspensum three years later 2. Across the entire spectrum of vibsane natural products α-hydroxylation is very rare,3,4 occuring only at position 3 of the bridged 7-membered ring class [e.g.…”

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confidence: 99%

Towards the Total Synthesis of 3-Hydroxyvibsanin E

Schwartz¹,

Denton²,

Bernhardt³

et al. 2009

Synthesis

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In 1999 Fukuyama reported the isolation of 3-hydroxyvibsanin E (1) (Figure 1) from Viburnum awabuki 1 with an additional finding in Viburnum suspensum three years later. 2 Across the entire spectrum of vibsane natural products α-hydroxylation is very rare, 3,4 occuring only at position 3 of the bridged 7-membered ring class [e.g. 3-hydroxy-15-Omethylcyclovibsanin A (2), 5 furanovibsanin A (3), 6 and 3-O-methylfuranovibsanin A (4)6] ( Figure 1). Although, the assumed later stage p450 enzymatic oxidation 7 to introduce the single hydroxyl group at position 3 is biosynthetically elegant it posses a considerable increase in the degree of synthetic challenge over the non-hydroxylated family members. Recently, we disclosed a combined effort which resulted in the total syntheses of both (−)-epi-5-vibsanin E (5) 8 and (±)-vibsanin E (6). 9 On this basis we felt that the methodology devised to prepare 5 and 6, and the experience gained from individual efforts 10,11 on other vibsane natural products, could be applied to the more challenging hydroxylated family members, specifically 3-hydroxyvibsanin E (1) (Figure 1).Key to this endeavour would be the use of Davies' tricyclic advanced intermediate 7, 10 generated by means of two cycloadditions: 1) a rhodium-catalysed [4+3] cycloaddition to give 8 from 9, and 2) a subsequent heteronuclear [4+2] cycloadditon (Scheme 1). The tricyclic intermediate 7 has been effectively used in the synthesis of both (−)-epi-5-vibsanin E (5) 8 and (±)-vibsanin E (6) 9 as summarized in scheme 1. In order to apply 7 to the synthesis of 3-hydroxyvibsanin E (1), a regioselective C-H hydroxylation of one of the intermediates in Scheme 1 would be required. 12 In this paper, we summarize the model studies to develop a selective C-H hydroxylation, followed by its application to studies toward the total synthesis of (±)-3-hydroxyvibsanin E (1).Several reasonable approaches are available for the selective C-H hydroxylation of vibsane-related intermediates. Williams reported11f that Koser's reagent 13 [PhI(OH)(OTs)] was superior to that of Davis' reagent (PhCHONSO 2 Ph) 14 in producing 16, when investigating α-hydroxylation of tricycle 15. In the case of 7, however, Davies 10b found that the Davis' reagent was superior affording 17 in 53% yield. 10b Williams 11g found that a vastly improved protocol over both of the above procedures was the Rubottom oxidation 15 of 18 giving 19 in 80% yield (Scheme 2).With this knowledge in-hand the approach shown in scheme 3 toward 3-hydroxyvibsanin E (1) was taken. The stereospecfic cuprate addition product 10 8 was doubly deprotected to unmask the ketone and primary alcohol. Treatment of 20 with t-butyldimethylsilyl * c.williams3@uq.edu.au. NIH Public AccessAuthor Manuscript Synthesis (Stuttg). Author manuscript; available in PMC 2010 September 1. Figure 2), which occurred in high yield (71% over three steps) (Scheme 3).O-Allylation of the lithium enolate derived from 24 proceeded smoothly in 81% yield. The Claisen rearrangement occurred in only moderate yield to g...

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Chemical Conversion of Vibsanin C to Vibsanin E and Structure of 3-Hydroxyvibsanin E from Viburnum awabuki

Cited by 32 publications

References 6 publications

Towards the Total Synthesis of Vibsanin E, 15‐O‐Methylcyclovibsanin B,3‐Hydroxyvibsanin E, Furanovibsanin A, and 3‐O‐Methylfuranovibsanin A

Towards the Total Synthesis of Vibsanin E, 15‐O‐Methylcyclovibsanin B,3‐Hydroxyvibsanin E, Furanovibsanin A, and 3‐O‐Methylfuranovibsanin A

ChemInform Abstract: Chemical Constituents of Plants from the Genus Viburnum

Towards the Total Synthesis of 3-Hydroxyvibsanin E

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