Facile stereoselective reductions of enediones and cage diketones suing sodium borohydride-cerium(III) chloride

Marchand, Alan P.; LaRoe, William D.; Sharma, G. V. M.; Suri, Suresh Chander; Reddy, D. Narasimha

doi:10.1021/jo00359a054

Cited by 94 publications

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“…[13][14][15] A mixture of 10a and 10b was used in the next reaction without separation because of their * To whom correspondence should be addressed. -and trans-5,8-dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone (1a, 1b) were for the first time synthesized from 5,8-dihydroxy-1,4-naphthoquinone (naphthazazine) (6) as a starting material and racemic triol (3) was first synthesized from 7.…”

Section: Resultsmentioning

confidence: 99%

“…To avoid enolization, the selective 1,2-reduction was next performed with NaBH 4 in the presence of a catalytic amount of CeCl 3 . [13][14][15] Thus, methyl ether 9 was converted to a mixture of diols 10a and 10b by treatment with NaBH 4 in the presence of CeCl 3 in MeOH. [13][14][15] A mixture of 10a and 10b was used in the next reaction without separation because of their instability.…”

Section: Resultsmentioning

confidence: 99%

“…[13][14][15] Thus, methyl ether 9 was converted to a mixture of diols 10a and 10b by treatment with NaBH 4 in the presence of CeCl 3 in MeOH. [13][14][15] A mixture of 10a and 10b was used in the next reaction without separation because of their instability. Catalytic hydrogenation of a mixture of 10a and 10b with PtO 2 under hydrogen, followed by purification by column chromatography afforded 11a (cis) and 11b (trans) in 31 and 31% yield, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of cis- and trans-5,8-Dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone.

Arima

Yamada

Takeda

et al. 2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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Sch 49210 (2) is a novel metabolite having antitumor and inhibitory phospholipase D activities and was isolated from a fungal culture broth by Chu et al. in 1994. 1) Compound 2 contains a unique structure, ketobisepoxydecalone with a spiroacetal linkage through a naphthalene moiety. CJ-12, 372 (4) isolated by Sakemi et al. 2) was shown to possess DNA gyrase inhibition activity and is a spiroacetal compound with 1,8-naphtalenediol (5) as compound 2. Recently, investigations of analogous compounds of 2 and 4 have been reported and the syntheses of a series of these naturally occurring spiroacetal-bridged compouds were published.3-11) The synthesis of bisepoxide 2 and naphthalene dimer 4 has not yet been published, however, we initially began to synthesize key compounds 1a and 3 for 2 and 4 (Chart 1). In this paper, we describe the first synthesis of cis -and trans-5,8-dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone (1a, 1b) by two routes, and also the first synthesis of racemic triol 3. Results and Discussion2,3-Dihydro-5,8-dihydroxy-1,4-naphthoquinone (7) was synthesized from naphthazazine (6) as the starting material by applying the procedure 12) developed by Pearson et al. Reduction of 6 by 20 eq of stannous chloride under acidic conditions gave dihydro compound 7 in 90% yield (Chart 2). Diol 7 was used in the following procedure without purification because 7 is unstable to air-oxidation and returns to starting material 6 easily. Diol 7 was then reduced by treatment with large excess (24 eq) of NaBH 4 in the presence of a catalytic amount of CeCl 3 13-15) in tetrahydrofuran (THF) at room temperature to afford a mixture of 8a and 8b. Oxidation of a mixture of 8a and 8b using ceric ammonium nitrate (CAN) [16][17][18] as an oxidant in acetonitrile gave a mixture of 1a (cis) and 1b (trans).19) The mixture was separated by column chromatography to give crystals 1a and oil 1b in 34 and 50% yields, respectively (Chart 2). The stereostructures of 1a and 1b were decided as follows. The determination whether 1a and 1b are the cis or trans isomer by 1 H-NMR spectra presented great difficulty because each spectrum exhibits a complicated coupling pattern. Therefore, X-ray analysis of 1a was performed. The ORTEP view of 1a showed a cis diol structure and exhibited interesting stereochemical features as shown in Fig. 1. The cyclohexane ring adopts a half-chair conformation and two carbonyl groups in quinone are above so that they are apart from each cis hydroxyl group. From these results, it was proved that 1a and 1b are correspondent to a cis and trans diol, respectively.In the procedure shown in Chart 2, separation of 1a and 1b by column chromatography was difficult because their Rf values are very close in spite of the short process. We therefore developed another method for 1a and 1b as shown in Chart 3. Methylation of 6 by treatment with Ag 2 O and CH 3 I afforded 9 in 76% yield according to the procedure developed by Pearson and co-workers. 12) At first LiAlH 4 was used as a reducing agent, but 1,4-dihydroxy-5,8-dim...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Synthesis of cis- and trans-5,8-Dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone.

Arima

Yamada

Takeda

et al. 2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…4) to construct a 10-membered lactone moiety, and they started from the known endo-tricyclic Diels-Alder adduct 58 67) of cyclopentadiene and pbenzoquinone. Asymmetric centers were introduced by lipase-mediated enzymatic desymmetrization 68,69) of meso-diol, 70,71) which was obtained by reduction of 58. After oxidation to cyclohexanone 59, zinc-mediated Barbier-type allylation and subsequent oxy-Cope rearrangement 72) provided the allylated product as a single diastereomer.…”

Section: Synthetic Approaches To Sch 642305mentioning

confidence: 99%

Synthetic Studies of Natural 10-Membered Lactones, Mueggelone, Microcarpalide, and Sch 642305, Which Have Interesting Bioactivities

Ishigami

2009

Bioscience, Biotechnology, and Biochemistry

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A number of 10-membered lactones have been isolated as secondary metabolites, and many of them have interesting and potent activities. Because of synthetic and biological interests, many synthetic studies of these compounds have been made. This review summarizes synthetic approaches to three natural 10-membered lactones, mueggelone, microcarpalide, and Sch 642305. Mueggelone is an inhibitor of fish development, microcarpalide is a microfilament disrupting agent, and Sch 642305 is an inhibitor of bacterial DNA primase.

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“…Selective reduction was accomplished with NaBH 4 and CeCl 3 Á7H 2 O to give alcohol 11 in 83% yield. 17 Protection with TBSCl and imidazole gave a quantitative yield of the silyl ether 12. The acetate group was then removed by reduction using DIBAL to give the corresponding alcohol and esterification using cinnamoyl chloride and pyridine provided cinnamate ester 13 in 83% yield.…”

Section: Introductionmentioning

confidence: 98%

Design and synthesis of terpene based englerin A mimics using chromium oxide mediated remote CH 2 oxidation

Acerson

Bingham

Allred

et al. 2015

Tetrahedron Letters

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Facile stereoselective reductions of enediones and cage diketones suing sodium borohydride-cerium(III) chloride

Abstract: Intermediate previously reported by Bentley et al. (ref 5), but no details of synthesis or characterization were given.

Cited by 94 publications

References 1 publication

Synthesis of cis- and trans-5,8-Dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone.

Synthesis of cis- and trans-5,8-Dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone.

Synthetic Studies of Natural 10-Membered Lactones, Mueggelone, Microcarpalide, and Sch 642305, Which Have Interesting Bioactivities

Design and synthesis of terpene based englerin A mimics using chromium oxide mediated remote CH 2 oxidation

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