Ester Amination

The advent of sulfamate ester oxidative cyclization makes available a myriad of oxathia-zinane derivatives from simple alcohol precursors. These unusual heterocycles have enjoyed only sparing use despite their potential as electrophiHc azetidine equivalents. By contrast, five-membered ring sutfamidates and cycHc sulfates are broadly recog- 

This brief discussion on the synthetic utihty of oxathiazinanes is only intended to highhght the versatihty of these reagents. Readers who seek a more detailed review on the chemistry of sulfamidites and sulfamidates are referred to a recent, comprehensive account by LubeU [121]. Apphcations for these unusual heterocychc building blocks should see continued growth with the oxidative amination technologies now available for their preparation. 

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Me3SiI, CH2CI2, 25°, 15 min, 85-95% yield.Under these cleavage conditions i,3-dithiolanes, alkyl and trimethylsilyl enol ethers, and enol acetates are stable. 1,3-Dioxolanes give complex mixtures. Alcohols, epoxides, trityl, r-butyl, and benzyl ethers and esters are reactive. Most other ethers and esters, amines, amides, ketones, olefins, acetylenes, and halides are expected to be stable. 

A great advantage of catalyst 24b compared with other chiral Lewis acids is that it tolerates the presence of ester, amine, and thioether functionalities. Dienes substituted at the 1-position by alkyl, aryl, oxygen, nitrogen, or sulfur all participate effectively in the present asymmetric Diels-Alder reaction, giving adducts in over 90% ee. The reaction of l-acetoxy-3-methylbutadiene and acryloyloxazolidinone catalyzed by copper reagent 24b, affords the cycloadduct in 98% ee. The first total synthesis of ewt-J -tetrahydrocannabinol was achieved using the functionalized cycloadduct obtained [23, 33e] (Scheme 1.39). 

The sulfur analogue of the Hauser ortho-substitution rearrangement provides access to an arylacet-ic NSAID. Reaction of the aminobenzophenone 176 with ethyl methylthioacetate and tert-butyl hypochlorite gives the intermediate 178. The reaction probably proceeds by way of formation of the S-chlorinated sulfonium derivative 177 displacement on sulfur will lead to the salt 178. Treatment with triethylamine leads initially to the betaine 179. Electrocyelic rearrangement of that transient intermediate leads, after rearomatization, to the homoanthranilic acid 180. Internal ester-amine interchange leads then to indolone 181 [45]. The thiomethyl group is then removed with Raney niekel. Saponifieation of intermediate 182 affords bromfenac (183) [46J. 

Some pairs of functional groups such as alcohol, ester carboxylic acid, ester amine, amide and carboxylic acid, amide can be interconverted by simple reactions. When a member of these groups is the desired product or starting material, the other member should also be consulted in the text. 

Most ruthenium-initiated ROMP studies have been performed using (233) and strained cyclo-olefinic monomers such as norbornene688 and cyclobutenes,689 although several reports on the polymerization of 8-membered rings have also appeared.690-692 A wide range of functionalities are tolerated, including ethers, esters, amines, amides, alcohols, carboxylic acids, and ketones. 

Alcohols, flavors, fragrances, fatty acid methyl esters, amines, acids... 

Polyarylketones resist acids at low concentrations, alcohols, aliphatic and aromatic hydrocarbons, greases, oils, gasoline, bases, most chlorinated solvents, ketones, esters, amines, and aldehydes. 

Classical organic chemistry provides a wide variety of potential analytes for electron ionization, the only limitation being that the analyte should be accessible to evaporation or sublimation without significant thermal decomposition. These requirements are usually met by saturated and unsaturated aliphatic and aromatic hydrocarbons and their derivatives such as halides, ethers, acids, esters, amines, amides etc. Heterocycles generally yield useful El spectra, and flavones, steroids, terpenes and comparable compounds can successfully be analyzed by El, too. Therefore, El represents the standard method for such kind of samples. 

Rule of thumb The stability of molecular ions roughly decreases in the following order aromatic compounds > conjugated alkenes > alkenes > alicyclic compounds > carbonyl compounds > linear alkanes > ethers > esters > amines > carboxylic acids > alcohols > branched alkanes. [81]... 

This picture is, however, incomplete because the dynamic nature of the amide bond is not taken into account. We have established through real-time IR spectroscopy that a rapid rearrangement of the hydroxyl-amide to the corresponding ester-amine (see Fig. 4) and vice versa allows a dynamic equilibrium between these two species which is strongly temperature dependent. Such a dynamic equilibrium has also been reported, albeit on a longer time-scale, for 4-hydroxyalkylamides [13]. 

A.S.H. Ong, K. Y. Cheah u. Y.M. Choo, Elaeis 1, 31-51 (1989) . .Oleochemicals from Palm Oil and Palm Kernel Oil [Production and Uses of Acids, Methyl Esters, Amines, and Alcohols derived from Palm and Palm Kernel Oils, and their Derivatives]". 

Unlike W and Mo catalysts, Rh catalysts are not suited to oriho-swhstxtutcd phenylacetylenes because Rh catalysts are rather sensitive to the steric effect. Instead, Rh catalysts are suitable to various phenylacetylenes having polar groups (e.g., ether, ester, amine, carbazole, imine, nitrile, azobenzene, nitro groups) at ra-position, resulting in the formation of high MW poly(phenylacetylenes). Many such examples are found in Table 3. 

Other ortho-acid derivatives which will not be considered in detail in this chapter are the thio ortho esters, amide acetals, ester aminals, and the ortho amides which have the following structures, respectively, RC(SR)3, RC(OR)2-NR2, RC(OR)(NR2)2, and RC—(NR2)3. 

Fig. 12. Reaction of monoalkyl monohydrogen phthalate with aniline. [Ester] = [Amine] = 0.25 M, T = 70 °C, Solvent = DMSO-d6. ( ) trifluoroethyl ester ( ) 1,3-dichloroisopropyl ester ( ) ethylglycolyl ester (A) propargyl ester (T) methyl ester...

Thiolate ions are also useful for the demethylation of certain ethers,761 esters, amines, and quaternary ammonium salts. Aryl methyl ethers762 can be cleaved by heating with EtS... 

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