Dienes diols

Madindoline A (7) and B (ent-8) are potent inhibitors of interleukin 6. In a total synthesis [21] that also intended to determine the relative and absolute configurations of these novel antibiotics, the densely functionalized cyclopen-tene-l,3-dione ring of 7 and 8 was elaborated via RCM of diene-diol 2 (Scheme 1). 

The ADMET polymerization of sugar-based monomers is much less explored than the ROMP approach, and only a few examples have been reported to date. Bui and Hudlicky prepared a,oo-dienes derived from a biocatalytically synthesized diene diol, from which chiral polymers (up to 20 kDa) with D-c/uro-inositol units were prepared via ADMET in the presence of 1 mol% of C4 [169]. Furthermore, several ot,co-dienes containing D-mannitol, D-ribose, D-isomannide, and D-isosorbide have been synthesized by Enholm and Mondal [170]. Also in this study, C4 was used to catalyze the ADMET polymerizations at 1 mol% catalyst loading. As pointed out by the authors, the viscosity increased as the reactions progressed and vacuum had to be applied to efficiently remove the released ethylene. Unfortunately, the polymers obtained were not further analyzed. As already mentioned above, Fokou and Meier have also reported the ADMET polymerization of a fatty acid-/D-isosorbide-based a,co-diene [126]. Furthermore, Krausz et al. have synthesized plastic films with good mechanical properties by cross-linking fatty esters of cellulose in the presence of C3 [171-173]. 

The meso-diene-diol 26 can be isomerized to the optically active alcohol 27 in quantitative yield and 43 % ee (Scheme 8) [12]. 

Enzymatic dihydroxylation of toluene by Pseudomonas putida affords (-t-)-cis-l, 2-dihy-droxy-3-methyl-3,5-cyclohexadiene) (Figure 33). The relative stereochemistry was determined to be ds, but the absolute configuration was unknown, until determined by Ziffer et al. [43] Catalytic reduction of the diene gave a stereochemically well-resolved cyclohexane diol suitable for introducing the benzoate chromophore. The dibenzoate gave a (-) exciton chirality CD, and thus the organism produces the diene-diol shown in Figure 33(a). 

Figure 33. (a) and (c) cis-dihydroxylation of toluene to give enantiomeric diene-diols, and catalytic reduction to the corresponding cyclohexane-1,2-diols. (b) cYc "... 

Clever entries to enantiopure carbapyranoses exploited optically pure or meso cw-diene diols easily obtained from aromatic compounds by... 

Johnson et al. used their newly developed orthoester Claisen reaction to achieve a highly stereoselective total synthesis of aM-trans squalene (5)1 (Scheme 1.20. The diene diol 6 underwent Johnson-Claisen rearrangement when it was heated with ethyl orthoacetate in the presence of propionic acid for 3 h at 138 C. The diene dialdehyde 7, obtained by treatment of the resulting ester with lithium aluminum hydride followed by oxidation with Collins reagent, reacted with 2-propenyllithium to give the tetraene diol 8. The tetraene dialdehyde 9, which... 

The use of copper chromite at 40°C and atmospheric pressure was not very effective for selective carbonyl group hydrogenation. Unsaturated alcohols were produced from unsaturated aldehydes in low yields at low conversions and not at all from methyl vinyl ketone. 28 With unconjugated, unsaturated aldehydes, copper chromite is effective as a selective hydrogenation catalyst. Hydrogenation of 46 at 140°-160°C and 200 atmospheres gave better than 70% of the diene diol, 47. Increasing the temperature to 240°C resulted in the complete saturation of 46 (Eqn. 18.28). 29... 

Sequences 1,2, and 3 of Scheme 3.25, to yield unsaturated epoxy alcohols. In Sequence 1, the terminal epoxide was isolated prior to conversion to trans 5S)-55. Sequence 2 of Scheme 3.25 illustrates the complete unraveling of the C-glycoside to yield a conjugated diene diol as a reaction competing with the formation of the desired epoxy alcohol. The formation of compounds such as the diene diol formed the basis for one of the syntheses of LTB4 described earlier in Scheme... 

C, Synthesis.—Atisine and Veatchine Types. Zalkow and co-workers developed syntheses of intermediates potentially transformable into atisine-type alkaloids, starting with podocarpic acid. The general approach is illustrated by a synthesis" of an ajaconine degradation product. Methyl O-methyl-7-keto-podocarpate (56) was reduced to the diol, which was converted by Birch reduction to dienone (57). The diene diol diacetate from this was converted to the 7,8-epoxide. Boron trifluoride converted this to the non-conjugated enone (58) which isomerised and... 

A compound first described in 1937 as the A -enolic form (303) of cholestane-3,4,6-trione is now shown to be a diene-diol ether, (304) and/or (305), 276... 

The 1,3,2-dioxaphosphorin (375) is obtained from the reaction of the diene-diol form of pentane-2,4 -dione with complexes of phenylphosphonous dichloride with chromium carbonyl (374). ... 

The formation of chiral 1,2-diols can be achieved by dihydroxylation of benzene derivatives by using appropriate enzymes or whole cell systems, in particular Pseudomonasputida (5.89). This biotransformation reaction provides cyclohexa-diene diols in essentially enantiopure form. Many of these diols are commercially available and can be converted to a variety of different enantiomericaUy enriched compounds. For example, protection of diol 90 as its acetonide and aziridination... 

Report. Thus, the groups of Yamamura and of Pattenden have disclosed a closely related route to citreoviral (247), which is based on preparation of the diene-diol intermediate (245), followed by epoxidation and cyclization to the substituted tetrahydrofuran... 

Figure 4. Design Features of Diene-diols 6 for Controlled Synthetic Operations.

Among bacteria that are capable of metabolizing arenes, certain strains express arene dioxygenase enzymes capable of effecting the dearomatizing dihydroxylation of an arene 1 to give a cis-cyclohexa-3,5-diene-l,2-diol 2 (Scheme 32.1). Ordinarily, such diene diols are merely fleeting... 

Polymers containing D-cfiiro-mositol units have been synthesized by ADMET [197], using a monomer derived from a biocatalytically synthesized diene diol. 

Scheme 16 Transfer hydrogenative diene-diol [4+2] cycloaddition. Yields are of material isolated by flash chromatography on silica gel. dppp = w-(diphenylphosphino)propane. BINAP = 2,2 -bis-(diphenylphosphino)-l,l -binaphthalene. dppPh = />(l,2-diphenylphosphino)benzene...

In 2005, Hanson et al. utilized this concept with a phosphate tether in the desymmetrization of C2-symmetric (3S,5S)-l,6-diene-diol (S,S)-24 (Scheme 4.9)... 

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