One-pot synthesis of -sulfonylamidines from -acylsulfonamides enabled by a metal triflate-mediated nonhydrolytic -deacylation.

A triflate salt-catalyzed nonhydrolytic method for the deacylation of -acylsulfonamides and subsequent one-pot condensation of the newly formed sulfonamides with ,-dimethylformamide dimethyl acetal to provide -sulfonylamidines is presented. A range of aliphatic and aromatic -acylsulfonamides bearing various -acyl groups such as acetyl, propionyl, butyrl, isobutyryl, octanoyl, benzoyl, 2-phenylacetyl, and sterically hindered pivaloyl are readily transformed into the corresponding -sulfonylamidines in good to excellent yields. A variety of functional groups including halogeno, keto, nitro, cyano, hydroxyl, ether, and carboxylic ester are tolerated intact.

Ferric Chloride-Mediated Transacylation of -Acylsulfonamides.

Transacylation of -acylsulfonamides, which replaces the -acyl group with a new one, is a challenging and underdeveloped fundamental transformation. Herein, a general method for transacylation of -acylsulfonamides is presented. The transformation is enabled by coincident catalytic reactivities of FeCl for nonhydrolytic deacylation of -acylsulfonamides and subsequent acylation of the resultant sulfonamides and can be conducted either stepwise or in a one-pot manner.

Chemoselective Cleavage of Acylsulfonamides and Sulfonamides by Aluminum Halides.

The chemoselective cleavage of C-N bonds of amides, sulfonamides, and acylsulfonamides by aluminum halides is described. AlCl and AlI display complementary reactivities toward -alkyl and -acyl moieties. -Alkylacylsulfonamides, secondary -(-butyl)sulfonamides, and tertiary -(-butyl)amides undergo N-dealkylation upon treatments with AlI generated in situ from aluminum and iodine in acetonitrile.

Cleavage of Carboxylic Esters by Aluminum and Iodine.

A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids.

Anchimerically Assisted Selective Cleavage of Acid-Labile Aryl Alkyl Ethers by Aluminum Triiodide and ,-Dimethylformamide Dimethyl Acetal.

Aluminum triiodide is harnessed by ,-dimethylformamide dimethyl acetal (DMF-DMA) for the selective cleavage of ethers neighboring group participation. Various acid-labile functional groups, including carboxylate, allyl, -butyldimethylsilyl (TBS), and -butoxycarbonyl (Boc), suffer the conditions intact. The method offers an efficient approach to cleaving catechol monoalkyl ethers and to uncovering phenols from acetal-type protecting groups such as methoxymethyl (MOM), methoxyethoxymethyl (MEM), and tetrahydropyranyl (THP) chemoselectively.

The multifaceted reactivity of o-fluoranil.

In addition to Diels-Alder and hetero-Diels-Alder reactions, tetrafluoro-o-benzoquinone (o-fluoranil) undergoes nucleophilic additions, addition-eliminations, dioxole formation, and charge-transfer complexation, reacting at every site on the molecular skeleton. It also effects dehydrogenations and other oxidations. The quinone can function as a (CF)(4) synthon.

o-Fluoranil: stereochemistry and mechanism of its Diels-Alder reactions.

In the absence of significant steric effects, Diels-Alder reactions of the title quinone generally take place with preservation of configuration, and are therefore probably concerted. However, hybrid density functional calculations indicate that often these reactions are highly asynchronous. Steric hindrance can result in reaction at quinone oxygen instead of carbon.

Unexpected fluorescence enhancement of naphthylethyl lauryl ether in coaggregation with variant aggregators.

Unexpected fluorescence enhancement has been observed during the coaggregation process between naphthylethyl lauryl ether (the fluorescence probe) and vitamin E acetate in aqueous organic binary solutions. Variant aggregators were used to study the influence of structure features on the enhancement. The experiments indicate that a long hydrophobic hydrocarbon chain is of necessity for coaggregation, and a flat group is crucial for the fluorescence enhancement.