合成路线1

2) (2R,3S,5S(2'S,4'R))-5-(2-(iodomethyl)tetrahydrofuran-4-yl)-5-(4-methoxy benzyloxy)-2-methyl-3-(triisopropylsilyloxy)pentanal (XXXII). The regioselective reduction of methyl 5-(4-methoxybenzyloxy)-3-oxopentanoate (XXI) with H2 over Ru2Cl4((S)-BINAP)2(C2H5)3N in methanol gives the 3(S)-hydroxy derivative (XXII), which is condensed with ally bromide (XXIII) by means of lithium diisopropylamide THF-HMPA to yield the ally derivative (XXIV). The reduction of (XXIV) with LiAlH4 in THF affords the diol (XXV), which is cyclized to the ketal (XXVI) by means of DDQ in dichloromethane. The reaction of (XXVI) first with N-iodosuccinimide (NIS) and then with diisobutylaluminum hydride affords (3S(2'S,4'R))-3-(2-iodomethyl)tetrahydrofuran-4-yl)-3-(4-methoxybenzyl)-1-propanol (XXVII), which is oxidized to the corresponding aldehyde (XXVIII) by means of oxalyl chloride in dichloromethane. The condensation of (XXVIII) with 2(E)-butenyltriphenylstannane (XXIX) by means of boron trifluoride ethearate in dichloromethane gives the alcohol (XXX), which is protected with TIPS trifluoromethanesulfonate in dichloromethane yielding the fully protected diol (XXXI). Finally, the double bond of (XXXI) is oxidized with ozone in methanol - dichloromethane yielding the second building fragment (XXXII).

合成路线2

A new total synthesis of FK-506 is described: This synthesis has been performed by previous construction of two building fragments (XXIV) and (LI), which later were coupled and cyclized. (Schemes 1-3): 1) (1R*S*,3R,5S,6R,7S,9R)-6-(tert-butyldimethylsilyloxy)-9-(1,3-dithian-2-yl)-5,7-dimethoxy-1-methyldecyl diphenyl phosphine oxide (XXIV). The Sharpless asymetric epoxidation of 1,4-pentadien-3-ol (I) with (-)-diisopropyltartrate and tert-butylhydroperoxide gives the epoxy alcohol (II) with high optical purity, which is benzylated in the usual way to (III). The reaction of (III) with lithioacetonitrile and then HCl yields lactone (IV), which is methylated with lithium diisopropylamide and methyl iodide to lactone (V) as major isomer (separated by chromatography on SiO2). The reduction of (V) with LiAlH4 affords the diol (VI), which is converted into the bis(tert-butyl carbonate) (VII) with 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile (BOC-N). The reaction of (VII) with Br2 and K2CO3 in dichloromethane gives the bromocarbonate (VIII), which by selective saponification of the cyclic carbonate with NaOCH3 in methanol yields the epoxy alcohol (IX). Methylation of (IX) with NaH and methyl iodide affords the methyl ether (X), which is converted into the butyrolactone (XI) with lithioacetonitrile as before. The protection of the OH group of (XI) with TBS-Cl gives the silyl ether (XII), which by trans-selective methylation with lithium diisopropylamide and methyl iodide yields lactone (XIII). The reduction of (XIII) with LiAlH4 affords diol (XIV) as major isomer (separated by column chromatography). The selective esterification of the primary OH group of (XIV) with pivaloyl chloride gives the hydroxy ester (XV), which is methylated with NaH and methyl iodide as usual to the methoxy derivative (XVI). Debenzylation of (XVI) by hydrogenolysis with H2 over Pd/C yields the hydroxy ester (XVII), which is silylated with TBS-SO3CF3 to the fully protected compound (XVIII).

合成路线3

The intermediate chiral 2-bromovinyl cyclohexane (XVIII) has been obtained as follows: The asymmetric epoxidation of divinyl carbinol (I) by means of L-(+)-diisopropyl tartrate, Ti(O-iPr)4 and tBu-OOH gives the epoxy alcohol (II), which is protected with p-methoxybenzyl bromide and NaH in THF to yield the benzyl ether (III). The condensation of (III) with the lithium derivative of ethyl acetate (IV) by means of BF3/Et2O, followed by hydrolysis with LiOH affords the 6-heptenoic acid (V). The methylation of the OH group of (V) with methyl iodide and NaH provides the corresponding methoxy acid (VI), which is esterified with diazomethane to give the methyl ester (VII). The debenzylation of (VII) by means of DDQ in dichloromethane yields the hydroxyester (VIII), which is cyclized by means of Ts-OH in refluxing benzene to afford the chiral tetrahydropyranone (IX). The Claisen rearrangement of the lactone (IX) catalyzed by Tbdms-OTf in refluxing toluene provides the cyclohexane carboxylic acid (X), which is esterified with diazomethane to give the methyl ester (XI). The hydroboration of the double bond of (XI) with BH3/THF, followed by protection with Tips-OTf yield the silyl ether (XII). The reduction of the ester group of (XII) with LiAlH4 affords the carbinol (XIII), which is treated with the Swern oxidant to afford the carbaldehyde (XIV). The condensation of (XIV) with the diazophosphonate (XV) and tBuOK provides the ethynyl cyclohexane (XVI), which is methylated with methyl iodide and BuLi in THF to give the propynyl cyclohexane (XVII). Finally, this compound is brominated by means of NBS and Cp2ZrHCl to yield the target intermediate, the chiral 2-bromovinyl cyclohexane (XVIII).

合成路线4

The total synthesis of (+)-resiniferatoxin started with the asymmetric Sharpless epoxidation of 1,4-pentadien-3-ol (I) to afford the epoxy-alcohol (II), which was further protected as the benzyl ether (III). Epoxide ring opening in (III) with the lithium acetylide (IV) in the presence of BF3 at -78 ºC yielded the acetylenic alcohol (V), which was subsequently cyclized to lactone (VI) under acidic conditions. Methylation of the lithium enolate of lactone (VI) gave rise to the trans- lactone (VII) as the major diastereoisomer. Addition of the lithiated derivative of O-(tert-butyldimethylsilyl)furfuryl alcohol (VIII) to the lactone (VII) produced the furyl ketone (IX). After protection of the hydroxyl group of (IX) as the corresponding acetate ester (X), reduction of its ketone function with NaBH4 furnished alcohol (XI). Oxidation of the furan nucleus of (XI) with m-CPBA produced the intermediate diketone (XII) which spontaneously cyclized to the pyranone (XIII). Acetylation of the hydroxyl group of (XIII) gave the (acetyloxy)pyranone (XIV).

合成路线5