An efficient enantiocontrolled synthesis of (+)-4-demethoxydaunomycinone

Gupta, Ramesh C.; Harland, Philip A.; Stoodley, Richard J.

doi:10.1016/s0040-4020(01)91527-3

Cited by 60 publications

(18 citation statements)

References 28 publications

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“…It was recrystallised from dichloromethane-diethyl ether-hexane to give (5aR,6aS,7R,lOaS, 1 1aS)-5a,l la-epoxy-5a,6a,7,10,lOa,l la-hexahydro-7-[( 2 (6 600), and 307 nm (2 400); 6(300 MHz; CDCl,) 0.30 (9 H,s,SiMe,),1.84,1.96,1.97,and 2.18 (each 3 H,s,together 4 x MeCO), 2.72br (1 H, d, J 18 Hz, lO-H,),3.16(1 H,dd,J7and4Hz,6a-H),3.60(1 H,ddd,J9.5,5, and 2. 5 Hz,3.76br (1 H, t, J 6.5 and 6.5 Hz, 10a-H), 4.14 (1 H,dd,J 12 and 5 Hz,4.26 (1 H,dd,J 12 and 2.5 Hz,6'-H), 4.42 (1 H,d,J 8 Hz,4.57 (1 H,dd,J9.5 and 8 Hz,4.93 (1 H,t,J9.5 and 9.5 Hz,4.94 (1 H,dd,J 6 and 4.5 Hz,4.98(1 H,d,J6Hz,8-H),5.11(1H,t,J9.5and9.5Hzy3'-H), 7.75-7.85, 8.02-8.07, and 8.12-8.17 (2, 1, and 1 H, each m, together 1-, 2-, 3-, and 4-H) (the signal for 10-H, was partly obscured by the signal at 6 2.18); m/z (c.i.) 542 (30%), 541 (3373, 450 (2273, 379 (5773, 378 (5473, and 331 (100%) (Found: C, 56.7; H, 4.9.…”

Section: Methodsmentioning

confidence: 98%

“…In work relating to the total synthesis of (+)-4-demethoxydaunompcinone (4), we had occasion to prepare the D-glucosebased diene (5a). 6 It reacted with the epoxy tetraone (6) to give one major cycloadduct, readily isolated by taking advantage of its insolubility in diethyl ether. Since the corresponding reaction of the dienophile (6) with Danishefsky's diene (5b) had been shown unequivocally to occur by way of the least-hindered , respectively] and of the double doublets (J 7.5 and 4 Hz) at 6 3.07 and 3.10 [attributed to the 6a-hydrogen atoms of compounds (7a) and (8), respectively].…”

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confidence: 99%

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Asymmetric Diels–Alder reactions. Part 1. Diastereofacial reactivity of (E)-3-trimethylsilyloxybuta-1,3-dienyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside towards cyclic dienophiles

Gupta¹,

Raynor²,

Stoodley³

et al. 1988

J. Chem. Soc., Perkin Trans. 1

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2AZ ~~The title diene (5a) reacted with p-benzoquinone in benzene at ambient temperature t o give an 8 9 : 11 mixture of (1 R,6R,IOS)-lO- [(2,3,4,6-tetra-O-acety~-~-~-g~ucopyranosy~)oxy] -8-trimethylsilyoxybicyclo[4.4.0]deca-3,8-diene-2,5-dione (9a) and its (1 Sr6S,1 OR) -diastereoisomer (1 Oa). The stereostructure of the major cycloadduct was established b y its conversion into (1 R,6R,IOS) -1 0 - [ ( 2,3,4,6 -tetra -0 -a cet y I -p -D -g I u c o p y r a n osy I ) ox y ] b i c y c I o [ 4.4.01 d eca n e -2,5,8t r i o n e ( 1 2), t h e s t r u cture of which was determined by X-ray crystallography. The diene (5a) showed a similar diastereofacial selectivity in its reactions with 2-methoxycarbonyl-p-benzoquinone [to give an 88: 1 2 mixture of the cycloadducts (9b) and (lob)], 2-acetyl-p-benzoquinone [to yield a 75: 25 mixture of the cycloadducts f Part of this work was carried out in the Department of Organic Chemistry at the University of Newcastle upon Tyne.endo transition state to give the racemic modification of the cycloadduct (7b)',$ the major cycloadduct arising from compounds (5a) and (6) possessed the stereostructure (7a) or (8). By virtue of its transformation into (+)-4demethoxydaunomycinone (4), the major cycloadduct was assigned the stereostructure (7a).6 In this paper, we examine the diastereofacial reactivity of the diene (5a) towards the epoxy tetraone (6) and related cyclic dienophiles. Results and DiscussionPreviously,6 it was found that the diene (5a) reacted with compound (6) in benzene at ca. 5 "C to give predominantly an 80:20 mixture of the cycloadducts (7a) and (8). The ratio was estimated by 300 MHz 'H n.m.r. spectroscopy (CDCl,) from the integrals of the doublets (J 18 Hz) at 6 2.73 and 2.84 [attributed to the l0a-hydrogen atoms of compounds (8) and 1 Following previous practice, we have used the Brockmann system of numbering and lettering (H. Brockman, Fortschr. Chem. Org. Naturst., 1983, 21, 121) to describe compounds (7a and b) and their derivatives.Earlier and throughout this work, the up-notation is applied in the standard manner to the aglycones of the major cycloadducts of the diene (5a) and their derivatives; the descriptors are used in an opposite sense to describe the aglycones of the minor cycloadducts and their derivatives (because their absolute configuration is inverted).Cycloadducts of the diene (5b) and their derivatives are, of course, produced as racemic modifications. Only single enantiomers are represented in this paper, which, arbitrarily, correspond to the major cycloadducts of the diene (5a) and their derivatives; the +notation is applied to these representations in the standard manner. the 2,3-double bonds of the quinones more reactive than their 5,6-counterparts. They were also expected to control the regiochemical outcome of the cycloaddition reactions. Finally, it was envisaged that the dione moieties would dominate any * The ratio reported in ref. 1 is unreliable.* When J" 14 Hz, rather than J" 11 Hz, is used in the Karplus equation, the angles calculated from ...

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Section: Methodsmentioning

confidence: 98%

mentioning

confidence: 99%

Asymmetric Diels–Alder reactions. Part 1. Diastereofacial reactivity of (E)-3-trimethylsilyloxybuta-1,3-dienyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside towards cyclic dienophiles

Gupta¹,

Raynor²,

Stoodley³

et al. 1988

J. Chem. Soc., Perkin Trans. 1

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“…From the results, it is clear that better stereoselectivities are observed with the reactants 1a, 1,5 1b, 2,6 1c, 1 1e 1 and 1f 1 (i.e. R 2 = alkyl group) than with the reactants 1d 7 That the major epoxide arising from the reaction of the vinylogous ester 1a with DMDO possessed the stereostructure 6a was established by X-ray crystallography** (Fig. 1).…”

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confidence: 90%

Stereoselective epoxidations of vinylogous esters/carbonates directed by the 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl auxiliary: a route to near stereopure tertiary alcohols bearing functional arms

Bhatia¹,

Pritchard²

1997

Chem. Commun.

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“…Over the past few years, we have demonstrated that anomerically linked glycopyranose units can confer a useful degree of facial reactivity on 1-oxybuta-1,3-dienes in cycloaddition reactions. [1][2][3][4][5][6][7][8][9][10][11][12][13] For example, the diene 1 displays good Re-face ‡ reactivity and undergoes highly endo-selective Diels-Alder reactions, 1,2,7 with cyclic dienophiles of type 2 to give predominantly cycloadducts of type 3. As well as endeavouring to understand the basis of the stereoinduction, we have sought to employ such cycloaddition reactions in the assembly of compounds of biological importance.…”

Section: Introductionmentioning

confidence: 99%

Studies related to carba-pyranoses: synthesis of acetylated derivatives of 4-amino-2,4-dideoxy-3-O-(β-d-glucopyranosyl)-β-l-(and β-d-) altrocarba-pyranose from ad-glucose template

Pritchard¹,

Stoodley²,

Yuen

2005

Org. Biomol. Chem.

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Methyl (E)-3-nitroacrylate 15, the X-ray analysis of which is reported here, is prepared from methyl acrylate by a new route involving sequential reactions with mercury(II) chloride-sodium nitrite, bromine and sodium acetate. The dienophile 15 reacts with Danishefsky's diene 17 to give, after acidic hydrolysis, a 67 : 33 mixture of the ketones rac-18 and rac-19. With (E)-1-(2',3',4',6'-tetra-O-acetyl-beta-D-glucopyranosyloxy)-3-(trimethylsiloxy)buta-1,3-diene 1, it affords, after hydrolysis, a 42 : 18 : 28 : 12 mixture of the ketones 30, 31, 32 and 33. The alcohol 36, obtained by sodium borohydride reduction of the ketone 30, is converted into the monocarba-disaccharide 35 by the action of aluminium amalgam, lithium aluminium hydride and acetic anhydride. Similarly, the alcohol 41, derived from the ketone 32, is transformed into the monocarba-disaccharide 40; the structure of the alcohol 41 is secured by an X-ray analysis. The isolation of a mixture of the acetoxyamino and acetylamino derivatives 38 and 39 from the reaction of the alcohol 36 with aluminium amalgam and acetic anhydride indicates that the nitro function is converted into the hydroxylamino and amino groups by the reducing agent. The cyclohexane rings of the ketones rac-18, rac-19, 30, 31 and 33 adopt the expected chair conformations. Thus, the methoxycarbonyl, nitro and oxy substituents are equatorially orientated in the ketones rac-18 and 30; in the ketones rac-19, 31 and 33, the methoxycarbonyl and nitro groups occupy equatorial dispositions and the oxy substituent is axially orientated. The cyclohexane ring of the ketone 32 (which bears a diastereomeric relationship to that of the ketone 30) displays unexpected conformational properties, that are attributed to a significant population of the chair conformer with axial arrangements of the methoxycarbonyl, nitro and oxy groups.

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An efficient enantiocontrolled synthesis of (+)-4-demethoxydaunomycinone

Cited by 60 publications

References 28 publications

Asymmetric Diels–Alder reactions. Part 1. Diastereofacial reactivity of (E)-3-trimethylsilyloxybuta-1,3-dienyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside towards cyclic dienophiles

Asymmetric Diels–Alder reactions. Part 1. Diastereofacial reactivity of (E)-3-trimethylsilyloxybuta-1,3-dienyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside towards cyclic dienophiles

Stereoselective epoxidations of vinylogous esters/carbonates directed by the 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl auxiliary: a route to near stereopure tertiary alcohols bearing functional arms

Studies related to carba-pyranoses: synthesis of acetylated derivatives of 4-amino-2,4-dideoxy-3-O-(β-d-glucopyranosyl)-β-l-(and β-d-) altrocarba-pyranose from ad-glucose template

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