Nitrate, allylic, reduction

N-acetyl-phenethylamine. Place 100 ml of acetonitrile and 64.8 g (.2 mole) of mercuric nitrate in a flask with stirring and cool to 25°. To this externally cooled and stirred mixture add 0.2 mole of allyl benzene at such a slow rate as to keep the temp under 30°. After the addition, stir at room temp for 1 hour, cool again, and achieve the reduction by adding 200 ml of 3 M sodium hydroxide, followed by 200 ml of. 5 M sodium borohydrate in 3 M sodium hydroxide. After 1 hour the water layer is saturated with sodium chloride and the product taken up with (extracted with) ether. Distillation, collect the fraction coming over at 101-105°. Yields 20 g of product. 

The cyclohexadiene complex 29 has been further elaborated to afford either the cydo-hexenone 34 or the cyclohexene 36 in moderate yields (Scheme 1) [21]. The addition of HOTf to 29 generates the oxonium species 33, which can be hydrolyzed and treated with cerium(IV) ammonium nitrate (CAN) to release the cyclohexanone 34 in 43 % yield from 29. Alternatively, hydride reduction of 33 followed by treatment with acid eliminates methanol to generate the r 3-allyl complex 35. This species can be trapped by the conjugate base of dimethyl malonate to afford a cyclohexene complex. Oxidative decomplexation of this species using silver trifluoromethanesulfonate liberates the cyclohexene 36 in 57 % overall yield (based on 29). 

A thoughtful reader would have noticed that, while plenty of methods are available for the reductive transformation of functionalized moieties into the parent saturated fragments, we have not referred to the reverse synthetic transformations, namely oxidative transformations of the C-H bond in hydrocarbons. This is not a fortuitous omission. The point is that the introduction of functional substituents in an alkane fragment (in a real sequence, not in the course of retrosynthetic analysis) is a problem of formidable complexity. The nature of the difficulty is not the lack of appropriate reactions - they do exist, like the classical homolytic processes, chlorination, nitration, or oxidation. However, as is typical for organic molecules, there are many C-H bonds capable of participating in these reactions in an indiscriminate fashion and the result is a problem of selective functionalization at a chosen site of the saturated hydrocarbon. At the same time, it is comparatively easy to introduce, selectively, an additional functionality at the saturated center, provided some function is already present in the molecule. Examples of this type of non-isohypsic (oxidative) transformation are given by the allylic oxidation of alkenes by Se02 into respective a,/3-unsaturated aldehydes, or a-bromination of ketones or carboxylic acids, as well as allylic bromination of alkenes with NBS (Scheme 2.64). 

Schnider and Grtissner in the same way prepared 3- and 2- (or 4) hydroxy-N-methylmorphinane, obtained the same compounds from N-methylmorphinane by way of the nitro and amino compounds, and also synthesized the 3-hydroxy-derivative from [liv] by nitration, reduction, diazotization, c., followed by cyclization [25]. They have more recently resolved [lxxih] and prepared 3-hydroxy-N-allyl-morphinane [26], Schnider and Hellerbach [27] prepared an isomer of [lxxiii] and also synthesized dZ-tetrahydrodesoxycodeine [lxxv] by the cyclization of [lxxvi], in which reaction a small amount of 2 3-dihy-droxy-N-methylmorphinane [lxxvii], isomeric with dZ-tetrahydrodes-oxymorphine, was also obtained. Both [lxxhi] and [lxxvii] exhibit marked analgesic properties to about the same extent, whilst the 2- (or 4) hydroxy-compound is much less active [25, 27]. 

Star and dendrimer core molecules were prepared by the peralkylation or allylation of cyclopentadienyliron complexes containing methyl-substituted arenes.298,301,302,304-311,333 The preparation of water-soluble metallodendrimers containing six cationic cyclopentadienyliron moieties, 281, has also been reported.301 Dendrimer 281 was tested for potential use as a redox catalyst for the cationic reduction of nitrates and nitrites to ammonia. 

Figure 1 shows the effect of the reduction temperature of a Co/silica-alumina catalyst, prepared from cobalt nitrate, on the selectivity to allyl alcohol. The higher reduction temperature resulted in a catalyst with a larger crystallite size of arbalt and a higher selectivity. The presence of residual Co in the catalysts reduced at lower temperatures could have some electronic effect on the hydrogenation. However, cobalt salts added into the reaction mixture scarcely affected the selectivity as will be shown below. The results for the catalysts with different cobalt loadings also... 

The (S)-lactone acid 1, obtained from L-glutamic acid by nitrous acid deamination, was converted to the acid chloride, then treated with excess diazomethane followed by hydrogen iodide to yield the keto-lactone 2. Amidation occurred quantitatively to give the partially racemized amide 3, which was purified by repeated recrystallizations. The vicinal diol resulting from reaction with excess methylmagnesium iodide was protected as the acetonide 4. An isomeric mixture of olefins (Z , 26 74) was obtained from the subsequent Wittig reaction. Reduction followed by separation on silver nitrate coated silica gel gave the (Z)-and ( )-alcohols in 20% (6) and 61% (5) yield, respectively. Conversion of the (S)-( )-alcohol (5) to the chloride then afforded the thioether (7) on reaction with sodium phenylsulfide. The thio ether anion was formed by treatment with n-butyllithium. Alkylation with the allylic chloride" (8), followed by removal of sulfur, then yielded the diene 9, which was converted in several steps to (/ ) (-t-)-10,11 -epoxy famesol. 

The chloride (62) thus obtained was resistant to subsequent hydrolysis to the alcohol (47). Therefore, (62) was quantitatively converted into (64) by treatment with sodium iodide in ethyl acetate. For replacement of the iodine in (64) with a hydroxy group, various methods were investigated. These included use of silver perchlorate in aqueous acetone, treatment with silver nitrate or a combination of sodium nitrate and methyl p-toluenesulfonate followed by reduction of the allylic nitrate intermediate with zinc and acetic acid, and application of the Evans method involving sulfoxide rearrangement [29]. A conversion method... 

Star polymers and dendrimers have been synthesized by Astruc using cyclopentadienyliron-mediated peralkylation, benzylation, and allylation reactions of cationic tri-, tetra-, and /iexa-methylbenzene cyclopentadienyliron com-plexes. " " These star and dendritic polymers contained cationic cyclopentadienyliron moieties at the core and/or the periphery. The cathodic reduction of nitrates and nitrites to ammonia has been achieved using a water-soluble dendrimer containing six cationic cyclopentadienyliron moieties as a redox catalyst. " The octametallic star (41) was prepared by deprotonation of permethylated iron complexes. ... 

Aza-adamantanes.—1-Aza-adamantanes are easily available in a convenient two-step synthesis from a-pinene (Scheme 83)." The synthesis is dependent on the serendipitous discovery that solvomercuration-demercuration of a-pinene with acetonitrile in the presence of mercuric nitrate followed by in situ boro-hydride reduction led not to the expected allylic amide but instead to azabicy-clo[3,3,l]nonene which is readily converted into aza-adamantane by reaction with formaldehyde. Rearrangement of A-chloro-N-acetyl-l-aminoadamantane... 

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