Copper-Catalyzed Iminoiodane-Mediated Aminolactonization of Olefins: Application to the Synthesis of 5,5-Disubstituted Butyrolactones

A copper(I)-catalyzed reaction of a variety of 4-aryl-pent-4-enoates with nosyliminoiodane generated <i>in situ</i> provides the corresponding 5-aryl-5-nosylamidomethylbutyrolactones. The reaction presumably proceeds <i>via</i> an aziridine intermediate, which could be isolated in one case

Iodine(III)-Mediated Umpolung of Bromide Salts for the Ethoxybromination of Enamides

Using (diacetoxyiodo)benzene in conjunction with simple bromide salts in ethanol allows the regioselective ethoxybromination of a wide range of enamides, thus yielding highly versatile α-bromo hemiaminals, which can then be engaged in a broad array of transformations

Iodine(III)-Mediated Umpolung of Bromide Salts for the Ethoxybromination of Enamides

Using (diacetoxyiodo)benzene in conjunction with simple bromide salts in ethanol allows the regioselective ethoxybromination of a wide range of enamides, thus yielding highly versatile α-bromo hemiaminals, which can then be engaged in a broad array of transformations

Chemodivergent, Tunable, and Selective Iodine(III)-Mediated Bromo-Functionalizations of Polyprenoids

Mild oxidation of bromides by iodine­(III) reagents generated active electrophilic bromination species that were reacted with polyprenoids. By simple and minor variations of an I­(III)/Br combination, the reactivity could be selectively steered toward dibromination, oxybromination, or bromocyclization, giving access to a wide array of brominated motifs

Chemodivergent, Tunable, and Selective Iodine(III)-Mediated Bromo-Functionalizations of Polyprenoids

Mild oxidation of bromides by iodine­(III) reagents generated active electrophilic bromination species that were reacted with polyprenoids. By simple and minor variations of an I­(III)/Br combination, the reactivity could be selectively steered toward dibromination, oxybromination, or bromocyclization, giving access to a wide array of brominated motifs

Diastereoselective Three-Component Vinylogous Mannich Reaction of Nitrogen Heterocycles, Acyl/Sulfonyl Chlorides, and Silyloxyfurans/pyrroles

A one-step, 3-component vinylogous Mannich reaction of trimethylsilyloxyfuran or <i>N</i>-protected <i>tert</i>-butyldimethylsilyloxypyrrole with a variety of nitrogen-containing heterocycles in the presence of diverse electrophiles is described. The reaction products were generally obtained in high yields and as a single diastereoisomer having the (<i>R</i>*,<i>R</i>*) relative configuration based on crystallographic studies of several derivatives. Several azaheterocycles were successfully used for this reaction, such as isoquinolines, quinoline, phenanthridine, quinazoline, phthalazine, and β-carboline, and electrophiles included acetyl chloride, methyl chloroformate, methyl chloromalonate, 2-bromobutanoyl chloride, and arylsulfonyl chlorides. The products of the vinylogous Mannich reactions were subjected to further transformations, leading to highly functionalized and stereochemically defined tetracyclic derivatives that are valuable building blocks for the preparation of natural products or medicinal agents

Diastereoselective Three-Component Vinylogous Mannich Reaction of Nitrogen Heterocycles, Acyl/Sulfonyl Chlorides, and Silyloxyfurans/pyrroles

A one-step, 3-component vinylogous Mannich reaction of trimethylsilyloxyfuran or <i>N</i>-protected <i>tert</i>-butyldimethylsilyloxypyrrole with a variety of nitrogen-containing heterocycles in the presence of diverse electrophiles is described. The reaction products were generally obtained in high yields and as a single diastereoisomer having the (<i>R</i>*,<i>R</i>*) relative configuration based on crystallographic studies of several derivatives. Several azaheterocycles were successfully used for this reaction, such as isoquinolines, quinoline, phenanthridine, quinazoline, phthalazine, and β-carboline, and electrophiles included acetyl chloride, methyl chloroformate, methyl chloromalonate, 2-bromobutanoyl chloride, and arylsulfonyl chlorides. The products of the vinylogous Mannich reactions were subjected to further transformations, leading to highly functionalized and stereochemically defined tetracyclic derivatives that are valuable building blocks for the preparation of natural products or medicinal agents

Chemodivergent, Tunable, and Selective Iodine(III)-Mediated Bromo-Functionalizations of Polyprenoids

Mild oxidation of bromides by iodine­(III) reagents generated active electrophilic bromination species that were reacted with polyprenoids. By simple and minor variations of an I­(III)/Br combination, the reactivity could be selectively steered toward dibromination, oxybromination, or bromocyclization, giving access to a wide array of brominated motifs

Halocyclization of Unsaturated Guanidines Mediated by Koser’s Reagent and Lithium Halides

The synthesis of halogenated cyclic guanidines through iodine­(III)-mediated <i>umpolung</i> of halide salts is described. Cyclic guanidines of various sizes can be obtained with generally excellent regioselectivities through either a chloro- or a bromocyclization, using Koser’s reagent and the corresponding lithium salt

Rhodium-Catalyzed Intramolecular Formation of <i>N</i>-Sulfamoyl 2,3-Aziridino-γ-lactones and Their Use for the Enantiospecific Synthesis of α,β-Diamino Acid Derivatives

4-Hydroxymethylbutenolide <b>4</b> was transformed into its sulfamoyl derivative <b>5</b>, which upon treatment with iodosobenzene diacetate and magnesium oxide in the presence of a rhodium catalyst afforded the product of intramolecular aziridination <b>6</b>. Reaction of <b>6</b> with primary or secondary amines in DMA led to regioselective opening of the aziridine ring at C2 to give the corresponding bicyclic derivatives <b>7a</b>–<b>7g</b> in good to excellent yields. Methanolysis of the lactone ring of the <i>N</i>-benzyl-<i>N</i>-methyl derivative <b>7c</b> followed by protection of the resulting secondary hydroxy group and treatment of the product with Boc anhydride provided the activated cyclic sulfamates <b>13</b> and <b>14</b>. The latter then reacted with a second nucleophile (azide or thiophenol) to give the corresponding difunctionalized α,β-diamino methyl esters <b>15</b>–<b>18</b>, <b>20</b>