Stereocontrolled synthesis of 2,4,5-trisubstituted tetrahydropyrans

Willis, C. L.; Simpson, Trey; Crosby, S. R.; Al-Mutairi, EH; SMITH, R. K.; Harding, JR; King, CD; Hughes, RA; Darzi, J

doi:10.1039/b101414p

Cited by 75 publications

(30 citation statements)

References 15 publications

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“…Under usual allylation conditions, such as reaction with sodium hydride (NaH) and allyl bromide in THF, no reaction occurred. Several examinations revealed that treatment of 5 with NaH and allyl iodide in the presence of 15-crown-5 in THF at room temperature afforded allyl ether (6) in 96% yield. Deprotection of TBDMS group with tetrabutylammonium fluoride (TBAF), followed by two stepoxidation with Dess-Martin periodinane and oxone in dimethylformamide (DMF) 26) gave carboxylic acid (7) in 80% overall yield.…”

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confidence: 99%

“…[3][4][5][6][7][8] The microtubule-stabilizing agent (Ϫ)-laulimalide, 9-18) also known as fijianolide B, which was isolated from several sponges (Cacospongia mycofijiensis,19) Hyattella sp., 20) Fasciospongia rimosa 21) ), contains 2,6-trans disubstituted 5,6-dihydro-2H-pyran as its C5-C9 portion. Stereoselective construction of thermodynamically less stable 2,6-trans substituted pyrans is one of most important subjects in synthesis of this attractive antitumor agent and its analogues.…”

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Stereoselective Synthesis of C3-C12 Dihydropyran Portion of Antitumor Laulimalide Using Copper-Catalyzed Oxonium Ylide Formation-[2,3] Shift

Yakura

Muramatsu

Uenishi

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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Tetrahydropyran and dihydropyran rings are structural components of a large number of natural products.1,2) Therefore, considerable attention has recently been directed toward their stereoselective synthesis. [3][4][5][6][7][8] The microtubule-stabilizing agent (Ϫ)-laulimalide, 9-18) also known as fijianolide B, which was isolated from several sponges (Cacospongia mycofijiensis,19) Hyattella sp., 20) Fasciospongia rimosa 21) ), contains 2,6-trans disubstituted 5,6-dihydro-2H-pyran as its C5-C9 portion. Stereoselective construction of thermodynamically less stable 2,6-trans substituted pyrans is one of most important subjects in synthesis of this attractive antitumor agent and its analogues.Metal catalyzed carbenoid reactions 22,23) have become a powerful tool for the synthesis of functionalized cyclic compounds including oxacycles. In 1994, Clark and co-workers reported that a copper-catalyzed reaction of 5-allyoxy-1-diazo-2-hexanone predominantly gave 2,6-trans-2-allyl-6-methy-3-dihydropyranone in good yield.24) This result stimulated us to investigate the metal catalyzed stereoselective synthesis of 2,6-trans disubstituted 3-pyranone (2) from adiazoketone (3) as a feasible method for synthesis of the C5-C9 portion of laulimalide and its analogues because 3 would be converted easily into the key intermediate (1) of the Mulzer's laulimalide synthesis, 11,25) as outlined in Chart 1. Herein, we describe the synthesis of 2 in high yield with excellent stereoselectivity by the copper-catalyzed oxonium ylide formation-[2,3] shift of 3 and conversion of 2 into 1 and its derivatives.a-Diazoketone (3) was prepared readily from the known alcohol (4) 11) as shown in Chart 2. Homoallylic alcohol (4) was converted to diol by hydroboration-oxidation process with borane-tetrahydrofuran (THF) complex and subsequent treatment with hydrogen peroxide and sodium hydroxide. Then the resulting primary hydroxyl group was protected as a tert-butyldimethylsilyl (TBDMS) ether to give the secondary alcohol (5) in high yield. O-Allylation of 5 was troublesome. Under usual allylation conditions, such as reaction with sodium hydride (NaH) and allyl bromide in THF, no reaction occurred. Several examinations revealed that treatment of 5 with NaH and allyl iodide in the presence of 15-crown-5 in THF at room temperature afforded allyl ether (6) in 96% yield. Deprotection of TBDMS group with tetrabutylammonium fluoride (TBAF), followed by two stepoxidation with Dess-Martin periodinane and oxone in dimethylformamide (DMF) 26) gave carboxylic acid (7) in 80% overall yield. Conversion of 7 into a-diazoketone (3) was achieved by the usual procedure, 27) formation of mixed acid anhydride with ethyl chloroformate and treatment with diazomethane, thereby providing 3 in 85% yield in two steps.With a-diazoketone (3) in hand, we turned our attention to cyclization of 3 by the metal catalyzed reaction (Eq. 1).(1)Formation of 2,6-disubstituted 3-pyranone using oxonium ylide formation-[2,3] shift of a-diazoketone has already been examined. Clark and co-worke...

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Stereoselective Synthesis of C3-C12 Dihydropyran Portion of Antitumor Laulimalide Using Copper-Catalyzed Oxonium Ylide Formation-[2,3] Shift

Yakura

Muramatsu

Uenishi

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Both the cis-and trans-alkenes yielded the same all-equatorial tetrahydropyran product. 229 Three-component phenol/aldehyde/nitrile one-flask reactions, such as that in equation 137, were also effective synthetic methods. 230 These reports have led to considerable interest in multicomponent tandem transformations that terminate with a Ritter reaction.…”

Section: Bridged Imine Formation and Reactivitymentioning

confidence: 99%

6.07 Ritter-Type Reactions

Bishop

2014

Comprehensive Organic Synthesis II

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“…The synthesis of substituted tetrahydropyran unit is important in organic chemistry because of its presence in many biologically active natural products [13][14][15][16][17][18][19][20]. Although there are many methods for the synthesis of halogenated [21][22][23][24][25], acetylated [26][27][28], arylated [29,30], hydroxylated [31][32][33] and amidated [34,35] tetrahydropyran, methods for the synthesis of fluorinated tetrahydropyran are limited [25,26,[36][37][38][39]. Prins cyclization is generally used for the construction of tetrahydropyran unit [40,41].…”

Section: Introductionmentioning

confidence: 99%