Addition, acetic acid to bicyclo

Addition, acetic acid to bicyclo[2.2.1]-hepta-2,5-diene to give nortri-cyclyl acetate, 46, 74 1,2,3-benzothiadiazole 1,1-dioxide to cyclopentadiene, 47, 8 benzyne to tetraphenylcyclopentadie-none, 46,107 Br, F to 1-heptene, 46,10 carbon tetrachloride to olefins, 46, 106... 

Addition, acetic acid to bicyclo[2.2.1]-hepta-2,5-diene to give nortri-cyclyl acetate, 46, 74... 

The electrophilic additions of formic and acetic acids to l,5-dimethyl-l,5-cyclooctadiene yielded mainly - 5yu-8-substituted-l,5-dimethylbicyclo[3.2.1]octanes (equation 10) via parallel jr-cyclization and subsequent Wagner-Meerwein (W-M) type rearrangement. Cross TT-cyclization leading to bicyclo[3.3.0]octane derivatives, which were the major adducts in other electrophilic additions to unsubstituted l,5-cyclooctadiene2 22 comprised only a minor route. This different behavior has been interpreted (equation 11) in terms of a significantly larger stability of the tertiary carbocation II than that of the secondary ion in, both ions being the two potential intermediates derived from I by a parallel and a cross jr-cyclization, respectively. 

The photochemical addition of ethene at 0°C in methylene chloride to the enedione (77) affords a high yield of the adduct (78). This was converted to the monochloro derivative (79) which also undergoes photoaddition of ethene to yield the Z> adduct (80). This on elimination of HCl yielded the quinol (81) which can be oxidised to the quinone (82). Cycloaddition of alkenes (cyclopentene, cyclohexene, and cycloheptene) has been carried out to the same enedione (77) to yield the adducts (83). lyoda et al. have also described a convenient synthesis of the bicyclo-octanediones(84) by a photochemical addition of alkenes to the enedione (77). The adducts (84) can be reduced by zinc in acetic acid to the desired products. Cycloaddition of ethyne to the same enedione followed by reduction affords the bicyclooctanes (85). The photoaddition of alkenes to the dibromo-enedione (86) is also effective and yields, after reduction, the adducts (87). 

N-Nitroso N phenylglycine, 46, 96 reaction with acetic anhydride to yield 3 phenylsydnone, 46, 96 Nitrosyl chloride, addition to bicyclo-[2 2 ljhepta 2,5 diene, 46, 75 2,4-Nonanedione, 47, 92 Nonane, 1,1,3 trichloro-, 46,104 Nortricyclanol, 46, 74 oxidation by chromic acid, 46, 78 Nortricyclanone, 46, 77 Nortncj clyl acetate 46, 74 frombicyclo[2 2 ljhepta 2,5 dieneand acetic acid, 46, 74 saponification of, 46, 75... 

The utility of tandem oxidative cyclizations is clearly demonstrated in substrates in which both additions are to double bonds [12]. Oxidative cydization of 20 with two equivalents of Mn(OAc)3 and of Cu(OAc)2 in acetic acid at 25 °C affords 86 % bicyclo[3.2.1]octane 25. Oxidation affords the a-keto radical 21, which cyclizes exclusively 6-endo in the conformation shown to afford the tertiary radical 22 with... 

A further variant is the oxidation of olefins by Mn(III) acetate in the presence of halide ions. Thus, oxidation of cyclohexene by Mn(III) acetate in acetic acid at 70°C is slow, but addition of potassium bromide leads to a rapid reaction. Cyclohexenyl acetate was formed in 83% yield.223 In contrast to what would be expected for an electron transfer mechanism, norbomene (ionization potential 9.0 eV) was unreactive at 70°C, whereas cyclohexene (ionization potential 9.1 eV) and bicyclo[3,2,l] oct-2-ene reacted rapidly. The low reactivity of norbomene can be explained, if oxidation involves attack at the allylic position... 

The reaction of alkenes with acetyl hypofluorite436-439 or with fluorine,451-473-474 2,3,4,5,6-pcntachloro-l-fluoropyridinium trifluoromelhanesulfonate ((V-FPCPy-OTf),441-711 cesium fluoroxysulfate,435 (V-fluorobis(triflyl)amine432 or l-(chloromethyl)-4-fluoro-l,4-diaza-bicyclo[2.2.2]octane tetrafluoroborate431 in acetic acid leads to the simultaneous addition of fluorine and the acetoxy group across the double bond. Examples of these additions are summarized in Table 34. Further examples are the formation of l439 and 2 439... 

The carbethoxy dienone 158 is isomerized smoothly to the bicyclo-hexenone product 160 in either dioxane or aqueous acetic acid, and no hydroxyketone formation could be detected. The noteworthy reluctance to incorporate solvent under acidic conditions in which hydroxyketone formation normally predominates has been ascribed to additional stabihzation of the cyclopropane bonds in the intermediate 159 towards hydrolytic cleavage (see Chart 26). 

Electrophilic additions to bicyclo[1.1.0]butanes are highly stereoselective. Protonation occurs predominantly with retention of configuration and leads to proton incorporation cis to the methyl moiety. Thus, acetolysis of l,2,2-trimethylbicyclo[1.1.0]butane (5) in acetic acid-d leads to the monodeuterated cyclopropylmethyl compounds 6 and 7 with retention of configuration. ... 

Treatment of bicyclo[4.1.0]heptan-2-ols with perchloric acid in acetic acid caused very clean rearrangement with formation of cyclohept-3-enyl acetates (Table 1). Only in the case of cxo-7-methylbicyclo[4.1.0]heptan-2-ol was the cyclohex-2-enyl acetate the major product probably because the 7-methyl group conferred additional stabilization on the carbocation formed by j0-scission of the outer cyclopropane bond. The same type of reactant could be oxidatively rearranged using pyridinium chlorochromate to afford cyclohepten-4-ones, together with (chloromethyl)cyclohexenes. However, if the chloride in the reagent was replaced with tetrafluoroborate, or if pyridinium chlorochromate was used with silver(I) nitrate, formation of the substituted cyclohexenes was completely suppressed, e.g. formation of 7 from 6, although the reported yields were low. ... 

The propellanes differ greatly in their reactivity with acetic acid. The relative rates of cleavage are in the following order [3.2.1]propellane > [4.2.1]propellane > bicyclo[2.1.0]pentane > [3.3.1]propellane. In addition to the cleavage reactions shown in Table 9 te-tracyclo[4.2.1.1. 0 ]decane reacts at its quaternary carbon atoms with dimethyl acetylenedicarboxylate to give mono- and bisadducts. ... 

From the established carbon-carbon connectivities in 304a, it was proposed that a possible precursor of the bicyclo[7.3.1]enediyne substructure could be C-14 chains such as 329 or 330, or their biogenetic analog, which can be connected with the anthraquinone moiety through a Friedel-Crafts type acylation reaction to form the C-8-C-9 bond and can also cyclize to the bicycle structure through two condensation reactions to form the C-3-C-4 and C-7-C-8 bonds. Introduction of an additional acetate unit at C-5 followed by oxidative degradation to form the carboxyl group and O-methylation from methionine should occur at some point. Tentatively, a heptacar-bonyl acid such as 331 was proposed as a possible precursor of the anthraquinone moiety. Moreover, an enediyne chain such as 329 is also conceivable as a precursor of the anthraquinone portion [332]. 

Bkycloheptane and Bicyclo-octane Derivatives.—Room temperature addition of diphenyldiazomethane to 7-t-butoxynorbornadiene yielded all of the possible 1,3-dipolar cycloaddition products (exo rule not obeyed). Pyrolysis of these adducts effects entry to the 3,3-diphenyltricyclo[3,2,l,0 ]octane system e.g. (852) is thus obtained. Procedures for the preparation of tricyclo[3,2,l,0 ]oct-6-ene-3-carboxylic acids, e.g. (853), essentially isomer-free have been described. Reductive dechlorination of (854), the Diels-Alder product of addition of 3,3-dimethylcyclo-propene to tetrachlorocyclopentadienone dimethyl acetal, followed by acetal hydrolysis and cheletropic loss of CO has been used to prepare 7,7-dimethylcyclohepta-triene. °... 

Enamines of cyclohexylamine have been enantioselectively cyclized to bicyclo[3.3.1] nonanedione systems, using acryloyl chloride and chiral pyrrolidine catalysis. Enantio-pure A-sulflnylimines have been used in asymmetric synthesis of isoquinolone alkaloids, and a stereocontrolled synthesis of 3,4,5,6-tetrahydropyrimidine-based amino acids from imino ethers has been reported. Diastereoselective additions of chiral acetals of (2-lithiophenyl)acetaldehyde to arylimines have been used in an asymmetric synthesis of 1-aryltetrahydroisoquinolines. " Organolithiums react with chiral imines, in the presence of Lewis acids or bases, to give amines in up to 100% de. Diastereoselective additions of copper reagents to imines derived from (5)-l-phenylethylamine have been reported. 

A mixture of bicyclo[2.2.1]heptadiene, glacial acetic acid, and tris(triphenyl-phosphine)platinum(O) heated 64 hrs. at 120° under Ng in an autoclave exo-5-acetoxybicyclo[2.2.1]hept-2-ene. Y 95%. E. F. Magoon and L. H. Slaugh, J. Organometal. Chem. 55, 409 (1973) n//-Markownikoff addition to prim, acoxy compds. by hydroboration-mercuration-iodination cf. R. C. Larock, J. Org. Chem. 39, 834 (1974). 

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