Cyclohexadiene diol

The successful synthesis of a high molecular weight precursor to polyphenylene that could be more readily converted to its corresponding conjugated polymer was reported where the prepolymer utilized ester substituents [95,96]. In a novel bacterial oxidation of benzene, a ds-cyclohexadiene diol 21 was initially prepared that was later acetylated and polymerized as shown in Scheme 26. This polymer was determined to contain approximately 90% 1,4-linkages and 10% 1,2-linkages. 

Hausmann T, Pietruszka J (2009) Enantiopure dicyclopropanes from trans-cyclohexadiene-diols. Synlett 21 3271-3274... 

Another versatile diene building block is cyclohexadiene diol [304], which can be obtained upon fermentation of halobenzenes. This building block is very versatile, and its potential as a synthon has not yet been much exploited in SPOS. However, its appHcability may be currently compromised by high price and lack of commercial accessibility in a stable pure form. The diene can be bound to a polymer bearing aldehyde or keto functions by transacetahzation. The acetal link to the polymer can readily be cleaved by dilute TFA, and this therefore serves as an excellent Hnkage system. The two double bonds of the cyclohexadiene have differ-... 

In 2007, Hudlicky and co-workers reported the preparation of enf-codeine (ent-2) with the enzymatically derived cyclohexadiene diol 49 as the starting material (Scheme 8) [50]. Key steps in this synthesis involve the introduction of the aryl moiety via a Mitsunobu reaction, a Heck reaction to establish the carbon bond between the aromatic ring and C13 followed by a second Heck reaction to close... 

The development of enzymatic dihydroxylation of aromatics has enabled synthetic access to a large collection of cyclohexadiene diols in enantiopure form. 

The same group also disclosed the synthesis of epz-7-deoxypaneratistatin via an aza-Payne rearrangement (254) (Scheme 7). Analogues of narciclasine (68), pan-crastistatin, and 7-deoxypancratistatin have been synthesized using modifications of the reported procedures as well as new methodologies (e.g. addition of indoles to oxiranes and aziridines derived from cyclohexadiene diols) (255-258). 

U. Rinner, Chiral Pool Synthesis Chiral Pool Syntheses from cis-Cyclohexadiene Diols, in Comprehensive Chirality,... 

Cyclohexadiene-d.s -diols as versatile intermediates in the synthesis of natural heterocycles 96CC1993. 

Cyclohexadiene has been prepared by dehydration of cyclohexen-3-ol,3 by pyrolysis at 540° of the diacetate of cyclohexane-1,2-diol,4 by dehydrobromination with quinoline of 3-hromocyclohexene,6 by treating the ethyl ether of cyclohexen-3-ol with potassium bisulfatc,6 7 by heating cyclohexene oxide with phthalic anhydride,8 by treating cyclohexane-1,2-diol with concentrated sulfuric acid,9 by treatment of 1,2-dibromocyclo-hexane with tributylamine,10 with sodium hydroxide in ethylene glycol,10 and with quinoline,6 and by treatment of 3,6-dibromo-cyclohexene with sodium.6... 

One 7i-bond of an aromatic ring can be converted to a cyclohexadiene 1,2-diol by reaction with enzymes associated with P. putida A variety of substituted aromatic compounds can be oxidized, including bromobenzene, chlorobenzene, " and toluene. In these latter cases, introduction of the hydroxyl groups generates a chiral molecule that can be used as a template for asymmetric syntheses. " ... 

An alternative new synthetic approach to chrysene 1,2-dihydro-diol based on Method IV has recently been developed (60). This method (Figure 12) entails synthesis of 2-chrysenol via alkylation of 1-1ithio-2,5-dimethoxy-1,4-cyclohexadiene with 2-(1-naphthyl) e-thyl bromide followed by mild acid treatment to ge nerate the diketone 12. Acid-catalyzed cyclization of 12 gave the unsaturated tetracyclic ketone 13 which was transformed to 2-chrysenol via dehydrogenation of its enol acetate with o-chloranil followed by hydrolysis. Oxidation of 2-chrysenol with Fremy s salt gave chrysene... 

Oxidation of conjugated dienes in CH3CN-NaC104 in the presence of 1,3-dimethylurea gives a mixture of the possible 4,5-disubstituted 1,3-di-methylimidazolidin-2-ones in about 40% yield.103 Anodic oxidation of 2,4-hexadiene, 1,3-butadiene, and 1,3-cyclohexadiene in CH3CN-H20-NaC104 yields diols, 2-oxazolines, and 3-pyrrolines.104 The product distribution is influenced by the supporting electrolyte. 

In a rather obscure, but synthetically very useful reaction, the biooxidative hydrox-ylation of chloro-benzenes (equation 23) has been used as a key step in the synthesis of inositols124. Cyclohexadiene c -diols are produced and similarly functionalized compounds may also be obtained from quinolines and isoquinolines125. These reactions have been exploited for the synthesis of a number of natural products126,127. 

Advantageous use of homochiral cyclohexadiene-cis-l,2-diol, available by means of biocatalytic oxidation of chlorobenzene with toluene dioxygenase, has enabled the synthesis of all four enantiomerically pure C18-sphingosines (Nugent, 1998), which are known inhibitors of protein kinase C and important in cellular response mediation for tumor promoters and growth factors. The four requisite diastere-omers of azido alcohol precursors were accessed by regioselective opening of epoxides with either azide or halide ions. 

Lorbach V, Franke D et al (2002) Cyclohexadiene-trams-diols as versatile starting material in natural product synthesis short and efficient synthesis of wo-crotepoxide and ent-senepox-ide. Chem Commun 38 494-495... 

A different approach has been used by Nakajima and his coworkers32 in the synthesis of inositols. Their starting materials were the cis- and trans-3,5-cyclohexadiene-l,2-diols (XIII and XV) ( benzeneglycols ) which... 

Borane-methyl sulphide complex 4-Toluenesulfonyl chloride cis-3,5-Cyclohexadiene-l,2-diol l -Dynamax 83,123-6 column Silver oxide Sodium hydride Palladium on charcoal Tetrabenzylpyrophosphate... 

Pseudomonas putida oxidation of benzene affords cis-3,5-cyclohexadiene-l,2-diol which is used as a novel precursor for the synthesis of D- and L-myo-inositol trisphosphates, which was prepared in 11 steps ... 

Freshly prepared sodium methoxide (0.1 ml of a 1 M solution in methanol, 10 mmol) was added dropwise to a solution of cis-3,5-cyclohexadiene-l,2-diol (112 mg, 1 mmol) in dimethyl carbonate (1.7 ml) and methanol (0.2 ml) at RT under argon, and stirred for 20 min. A small aliquot was removed, solvent evaporated in vacuum (bath T 22°C) and the resulting solid was washed with a small volume of chilled (-20°C) ether and chilled (-20°C) petrol (b.p. 30°-40°C) to afford the 3a,7a-dihydrobenzo[l,3]dioxol-2-one (cyclic carbonate) as a beige-coloured solid, mp 90°C (dec.). 

Microbially Produced Functionalized Cyclohexadiene-trans-diols as a New Class of Chiral Building Blocks in Organic Synthesis On the Way to Green and Combinatorial Chemistry... 

I 6.4 Microbially Produced Functionalized Cyclohexadiene-trans-diols... 

---