From cyclopentadiene

8 CARBOHYDRATES AND ANALOGS FROM ACHIRAL HYDROCARBONS 13.8.1 From Cyclopentadiene 

SCHEME 13.104 Hoffmann s asymmetric [4 + 3] cycloaddition of furan. Total syntheses of 2,6-anhydroheptitols. 

SCHEME 13.105 Synthesis of xylitol. Copyright 2006 by Taylor Francis Group LLC 

A total synthesis of 1,3-dideoxynojirimycin starting from cyclopentadiene was proposed by Johnson et al. [206]. Photooxidation of cyclopentadiene and reductive workup with thiourea generates c/ -cyclopent-2-ene-l,4-diol, which is monoacylated with high enantioselectivity ( 99% ee) with isoprenyl acetate and Candida antarctica lipase B (Novo Nordisk SP 435) to give 461. After silylation of 461 and subsequent treatment with KOH and oxidation, enantiomerically pure enone 462 is obtained [207]. 

A similar approach converted enantiomerically pure (2R,3R)-2,3-isopropylidenedioxy-cyclopent-4-en-l-one derived from cyclopentadiene [209] into (—)-l-deoxymannonojirimycin and (-)-l-deoxytalonojirimycin (l,5-dideoxy-l,5-imino-D-talitol) [210]. Enone 462 was converted to (2R,35 )-2,3-bis ( r -butyl)dimethylsilyloxy]cyclopent-4-en-l-one and then to (-f)-1 -deoxynojirimycin [211]. 

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Table 3. Diels-Alder Adducts from Cyclopentadiene...

Tropolone has been made from 1,2-cycloheptanedione by bromination and reduction, and by reaction with A -bromosuccinimide from cyolo-heptanone by bromination, hydrolysis, and reduction from diethyl pimelate by acyloin condensation and bromination from cyclo-heptatriene by permanganate oxidation from 3,5-dihydroxybenzoic acid by a multistep synthesis from 2,3-dimethoxybenzoic acid by a multistep synthesis from tropone by chlorination and hydrolysis, by amination with hydrazine and hydrolysis, or by photooxidation followed by reduction with thiourea from cyclopentadiene and tetra-fluoroethylene and from cyclopentadiene and dichloroketene. - ... 

The methods of preparation of ferrocene have been reviewed by Pauson and by Fischer. Ferrocene has been made by the reaction of ferric chloride with cyclopentadienylmagnesium bromide, by the direct thermal reaction of cyclopentadiene with iron metal, by the direct interaction of cyclopentadiene with iron carbonyl, by the reaction of ferrous chloride with cyclopentadiene in the presence of organic bases such as diethyl-amine, by the reaction of ferrous chloride with sodium cyclo-[lentadienide in liquid ammonia, and from cyclopentadiene and... 

Clavulones I and II are members of an unusual family of marine prostanoids from the coral Clavularia viridis which are biosynthesiied by a cationic (i.e. non-radical, non-endoperoxide) pathway. The total synthesis of clavulones I and II was accomplished from cyclopentadiene as SM goal. 

A small number of pyrroles undergo addition of acetylenedi-carboxylic acid across the 2,5-positions yielding adducts similar to those obtained from cyclopentadiene. In the case of 1-benzylpyrrole and the acid, some (13) is formed, probably through the intermediary of a species such as (8) a strong case has been made for the supposition that the Diels-Alder reaction occurs in two distinct stages,... 

Searching for donoracceptor-substituted anions as well as related cations derived from cyclopentadiene, the azafulvalene 32 was synthesized by condensation of the potassium salt of the pushpull-substituted cyclopentadiene with 3-methyl-2-methylsulfanyl-benzothiazolium tetrafluoroborate (85AG996) (Scheme 9). 

Thiazide diuretics have a venerable history as antihypertensive agents until the advent of the angiotensin-converting enzyme (ACE) inhibitors this class of drugs completely dominated first line therapy for hypertension. The size of thi.s market led until surprisingly recently to the syntheses of new sulfonamides related to the thiazides. Preparation of one of the last of these compounds starts by exhaustive reduction of the Diels-Alder adduct from cyclopentadiene and malei-mide (207). Nitrosation of the product (208), followed by reduction of the nitroso group of 209,... 

Active Figure 15.4 Generating the cyciopentadienyl cation, radical, and anion by removing a hydrogen from cyclopentadiene. Sign in afwww.thomsonedu.com to see a simulation based on this figure and to take a short quiz. 

The preparation of 5-ACETYL-l,2,3,4,5-PENTAMETHYLCYCLO-PENTADIENE is of value in the synthesis of pentamethyleyclo-pentadiene and many pentamethylcyclopentadienyl metal carbonyl derivatives that are more soluble in organic solvents than those derived from cyclopentadiene. Simple preparations of 5,6-DIHYDRO-2-PYRAN-2-0NE and 2-//-PYRAN-2-ONE make these hitherto rather inaccessible intermediates available for cycloaddition and other reactions. The already broad scope of the Michael reaction has been widened further by including an efficient preparation of ETHYL (E)-3-NITROACRYLATE. Workers in the field of heterocyclic chemistry will find a simplified method for the preparation of 2,3,4,5-TETRA-HYDROPYRIDINE of help. 

The cyclopentadienide ion, C H , is a common organic anion that forms very stable complexes with metal cations. The anion is derived by removing a proton from cyclopentadiene, QH, with strong base. The molecule has a five-memhered ring of carbon atoms, with four carbon atoms attached to only one proton and one carbon atom bonded to two. Draw the Lewis... 

Dihydro-lH-l,2-azaboroles derive from cyclopentadiene by the isoelectronic replacement of a C=C group by a BN moiety ". The neutral rings react in xs boiling Fe(CO)j without any other solvent to form red-brown iron-dihydro-1,2-azaborolyldi-carbonyl dimers as their cis and transisomers in 56% yield, or with CojfCOg in petroleum ether at 60-80°C to the half-sandwich complex (dihydro-1,2-azaborolyl)Co(CO)2 (40%). The CO group can easily be substituted by olefins ... 

The cis alcohol (45) is an obvious Simmons-Smith product (p T 257) since we require the CH group to be added from the same side as the hydroxyl group. The starting alcohol (46) was available from cyclopentadiene. 

A special class of synthesis is the utilization of retro-Diels-Alder (RDA) reactions. A double RDA sequence was used to prepare the pyrimido[l,2-A]pyridazin-3-one 118. In this versatile method both reactants of the parent compound were constructed from cyclopentadiene. The parent compound 117 contains two norbornene units and decomposes on heating in toluene in a double RDA reaction leaving two double bonds in the target heterocycle. Similarily, the parent compound 119 decomposes in a single RDA reaction to yield the benzologue, pyridazino[6,l-3]-quinazolin-10-one 120 (Scheme 13) <2000SL67>. 

In certain cases the initial Diels-Alder adducts of ADC compounds are labile. For example, the adduct (121) from cyclopentadiene and azodibenzoyl rearranges in quantitative yield on heating in aqueous methanol to give the 1,3,4-oxadiazine 122.207 Solvent has little or no effect, and a concerted [3,3] rearrangement as shown in Scheme 17 seems the most likely explanation. The rearrangement has been extensively studied by Mackay and coworkers,208 and it shows great dependence on substitution effects. 

Reactions of methoxycarbonylformonitrile, furonitrile and substituted benzoni-trile oxides (4-Me, 4-OMe, 3-OMe, 4-C1, 3-C1, 2,4-di-Cl, 4-F as substituents) with dimethyl 7-(diphenylmethylene)bicyclo[2.2. l]hept-2-ene-5,6-dicarboxylate led exclusively to exo cycloadducts 82 (R = C02Me, 2-furyl, substituted phenyl), which, on irradiation with a low-pressure mercury lamp, afforded 3-azabicyclo [4.3.0]nonadiene-7,8-dicarboxylates 83 as the only products. The 1,3-dipolar cycloaddition, followed by a photorearrangement, provides a new method for obtaining tetrahydro-27/ -pyridine derivatives from cyclopentadiene (245). 

A rapid access to carbocyclic nucleosides, containing a fused isoxazoline ring has been proposed, starting from cyclopentadiene. The route involves a het-ero Diels-Alder cycloaddition reaction of nitrosocarbonylbenzene followed by a 1,3-dipolar cycloaddition of nitrile oxides, cleavage of the N-0 tether and transformation of the heterocyclic aminols into nucleosides via construction of purine and pyrimidine heterocycles (457). 

The Tsuji-Trost reaction is the Pd(0)-catalyzed allylation of a nucleophile [48-51]. The NH group in imidazole can take part as a nucleophile in the Tsuji-Trost reaction, whose applications are found in both nucleoside and carbohydrate chemistry. Starting from cyclopentadiene and paraformaldehyde, cyclopentenyl allylic acetate 64 was prepared in diastereomerically-enriched form via a Prins reaction [52], Treating 64 with imidazole under Pd(0) catalysis provided the N-alkylated imidazole 65. 

See also Acetoacetyl-CoA in citric acid cycle, 6 633 Acetyl cyclohexanesulfonyl peroxide (ACSP), 74 282 78 478 Acetylene(s), 7 177-227, 227-228 25 633 addition of hydrogen chloride to, 73 821 from calcium carbide, 4 532, 548 carbometalation of, 25 117 as catalyst poison, 5 257t chemicals derived from, 7 227-265 decomposition of, 70 614 Diels-Alder adduct from cyclopentadiene, 8 222t direct polymerization, 7 514 economic aspects of, 7 216-217 explosive behavior of, 7 181-187 as fuel, 7 221-222 health and safety factors related to, 7 219... 

Diels-Alder adduct from cyclopentadiene, 8 222t economic aspects, 1 268-269 effect of unsaturation on toxicity, 2 69t health and safety factors, 1 280-281 2 67... 

Diels-Alder adduct from cyclopentadiene, 8 222t... 

Chlorohydroxotricyclohexylantimony, 3 7 7 /V-Chloroimines, 73 102 Chloroisocyanurates, 73 114, 115 Chloromaleic anhydride, Diels-Alder adduct from cyclopentadiene, 8 222t Chloromethane(s)... 

Diels-Alder adduct from cyclopentadiene, 8 222t physical properties, 5 31t, 37t 18-Crown-6, 7 588 Crown analogue inclusions, 74 162 Crown compounds, 74 160, 185. 

Diels-Alder adduct from cyclopentadiene, 8 222t Diels-Alder reactions of, 25 488-489 economic aspects of, 25 507-509 electrophilic addition of, 25 490 in ene reactions, 25 490 esterification of, 25 491 free-radical reactions of, 25 491 from butadiene, 4 371 Grignard-type reactions of, 25 491 halogenation of, 15 491—492 health and safety factors related to, 25 510-511... 

Nitrosamines, 2 449-451 Al-Nitrosamines, 15 531 Nitrosobenzene, Diels-Alder adduct from cyclopentadiene, 8 222t Al-Nitroso compounds, ascorbic acid and, 25 770... 

The effect of changing the position of the electron-donating atom in the side chain R of oxazaborolidine catalysts 367 was studied systematically for the reaction between cyclopentadiene and methacrolein. The enantioselectivity proved to be controlled by the presence of electron-donor atoms at positions 2 and 4 of the side chain. The effect was especially apparent in the formation of 366 from cyclopentadiene with a-bromoacrolein (365) (equation 105, Table 20), which is more electron-poor than methacrolein232. 

The iminium salt 132, generated from benzylamine hydrochloride and aqueous formaldehyde, reacts with cyclopentadiene during 3 h at room temperature to give, after basification, the cycloadduct 133 in nearly quantitative yield (equation 70). Other examples of this reaction are shown in equations 71-75. The separable diastereomers 134 and 135 are formed in the ratio 4 1 from cyclopentadiene, (—)-a-methylbenzylamine hydrochloride and aqueous formaldehyde in a combined yield of 86% (equation 75)62. Hydrochlorides 136 of methyl esters of natural amino acids [(S )-valine, (S )-isoleucine] react with cyclopentadiene and formaldehyde in aqueous THF to produce mixtures of the diastereomers 137 and 138, in which the former predominate (equation 76)63. 

Photooxygenation of a-terpinene 155 in the presence of eosin (equation 87) produces ascaridole 156, a constituent of the essential oil Chenopodium ambrosioides L 1. The ewrfo-peroxide 157 derived from cyclopentadiene is a crystalline solid, stable at —100 °C78 above this temperature it rearranges to a mixture of the bis-epoxide 158 and the epoxyaldehyde 159 (equation 88)79,80. 

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