Rhodinose derivatives suitable for the synthesis of anthracycline analogs

Khadem, H. El; Cermak, Richard C.

doi:10.1016/s0008-6215(00)84656-x

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…Ketone 9. Di-O-acetylrhamnal (5), obtained from L-rhamnose or commercial sources, was converted into the known benzyl glycoside 7 17 according to the Ferrier procedure. 18 Oxidation of the C-4 hydroxy group in the latter with pyridinium dichromate gave enone 8 in 67% overall yield (Scheme 2).…”

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confidence: 99%

New Chiral Pool Approach to Anthracyclinones. The Stereoselective Synthesis of Idarubicinone

Achmatowicz

Szechner

2003

J. Org. Chem.

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In the present work, a new chiral pool approach has been developed for the synthesis of anthracyclinones. Thus, enone 8, readily available from l-rhamnose, has been converted via addition of 2,5-dimethoxybenzyllithium to the carbonyl group and a series of six reactions into a suitably protected aldehyde 21. The SnCl(4)-promoted stereospecific cyclization of the latter afforded enantiopure key intermediate 22. Silylation of benzylic hydroxyl of 21 followed by anodic oxidation and selective hydrolysis gave ketoacetals 25 and 26 to which 3-cyano-1(3H)-isobenzofuranone 27 was annelated. Removal of the isopropylidene group in the resulting 28, subsequent oxidation of the C(13) hydroxyl and full deprotection led to idarubicinone (4).

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Section: Resultsmentioning

confidence: 99%

New Chiral Pool Approach to Anthracyclinones. The Stereoselective Synthesis of Idarubicinone

Achmatowicz

Szechner

2003

J. Org. Chem.

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“…During the course of our work on the synthesis of hexasaccharide 1 , we needed a convenient source of the l -rhodinosyl acetate derivative 3 for introduction of the C residue in the repeat trisaccharide 2 . l -Rhodinose, a 2,3,6-trideoxy- l -hexose, is a constituent of several classes of natural products including landomycin A, streptolydigin, and vineomycin B 2 . − Numerous syntheses of rhodinose and its derivatives are known in the literature, − including several that originate from more readily available sugars. − We were most attracted to the routes that originated from methyl ( S )-lactate 14,19,20 and adopted modifications of Schlessinger's route for synthesis of 3 . , …”

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confidence: 99%

Studies on the Synthesis of Landomycin A: Synthesis and Glycosidation Reactions of l-Rhodinosyl Acetate Derivatives

2001

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An efficient, eight-step synthesis of L-rhodinosyl acetate derivative 3 is described. The synthesis originates from methyl (S)-lactate and involves a highly stereoselective, chelate-controlled addition of allyltributylstannane to the lactaldehyde derivative 7. The beta-anomeric configuration of 3 was established with high selectivity by acetylation of the pyranose precursor with Ac(2)O and Et(3)N in CH(2)Cl(2). Preliminary studies of glycosidation reactions of 3 and L-rhodinosyl acetate 10 containing a 3-O-TES ether revealed that these compounds are highly reactive glycosidating agents and that trialkylsilyl triflates are effective glycosylation promoters. The best conditions for reactions with 15 as the acceptor involved use of diethyl ether as the reaction solvent and 0.2 equiv of TES-OTf at -78 degrees C. However, the TES ether protecting group of 10 proved to be too labile under these reaction conditions, and mixtures of 16a, 17, and 18a are obtained in reactions of 10 and 15. Disaccharide 17 arises via in situ cleavage of the TES ether of disaccharide 16a, while trisaccharide 18a results from a glycosidation of in situ generated 17 (or of 16a itself) with a second equivalent of 10. These problems were largely suppressed by using 3 with a 3-O-TBS ether protecting group as the glycosyl donor and 0.2 equiv of TES-OTf as the reaction promoter. Attempts to selectively glycosylate the C(3)-OH of diol acceptors 20 or 28 gave a 70:30 mixture of 21 and 22 in the reaction of 20 and a 43:27:30 mixture of regioisomeric trisaccharides 29 and 30 and tetrasaccharide 31 from the glycosidation reaction of 28. However, excellent results were obtained in the glycosidation of differentially protected disaccharide 34 using 1.5 equiv of 3 and 0.05 equiv of TBS-OTf in CH(2)Cl(2) at -78 degrees C. The latter step is an important transformation in the recently reported synthesis of the landomycin A hexasaccharide unit.

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Synthesis of via a tandem sharpless asymmetric dihydroxylation/lipase-catalyzed transesterification

Sobti

Sulikowski

1995

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Rhodinose derivatives suitable for the synthesis of anthracycline analogs

Cited by 5 publications

References 3 publications

New Chiral Pool Approach to Anthracyclinones. The Stereoselective Synthesis of Idarubicinone

New Chiral Pool Approach to Anthracyclinones. The Stereoselective Synthesis of Idarubicinone

Studies on the Synthesis of Landomycin A: Synthesis and Glycosidation Reactions of l-Rhodinosyl Acetate Derivatives

Synthesis of via a tandem sharpless asymmetric dihydroxylation/lipase-catalyzed transesterification

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