Diazocarbonyl Compounds Research Articles

Enantioselective intramolecular 1,3-dipolar cycloadditions of diazocarbonyl-derived oxidopyryliums

Catalytic enantioselective tandem oxidopyrylium formation intramolecular 1,3-dipolar cycloaddition reactions of phthalic anhydride-derived unsaturated diazocarbonyl compounds in up to 19% ee are described.

Asymmetric intramolecular cyclopropanation of diazo compounds with metallosalen complexes as catalyst: structural tuning of salen ligand

Intramolecular cyclopropanation of alkenyl α-diazoacetates and alkenyl diazomethyl ketones was examined by using optically active (ON +)Ru(II)(salen) and Co(II)(salen) complexes as catalysts. For the cyclization of 2-alkenyl α-diazoacetates, Co(II)(salen) complexes 9 and 10 were found to be superior catalysts to the corresponding (ON +)Ru(II)(salen) complexes 4 and 5. On the other hand, (ON +)Ru(II)(salen) complex 2 was found to be the catalyst of choice for the cyclization of 3-alkenyl diazomethyl ketones, and complex 4 was found to be a good catalyst for the cyclization of ( E)-4-alkenyl diazomethyl ketones. The present study demonstrates that metallosalen complexes, especially optically active (ON +)Ru(II)(salen) and Co(II)(salen) complexes, can serve as efficient catalysts for the cyclization of alkenyl diazocarbonyl compounds, if a suitable salen ligand is used as the chiral auxiliary.

Rh2(OAc)4‐Catalyzed Regioselective Intermolecular C—H Insertion Reactions: Novel Synthesis of 2‐Pyrrol‐3′‐yloxindoles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Investigation of the transition-metal- and acid-catalyzed reactions of beta-(N-tosyl)amino diazo carbonyl compounds.

A series of beta-(N-tosyl)amino diazo carbonyl compounds have been prepared by nucleophilic condensation of N-tosylimines with acyldiazomethanes. The diazo decomposition of these diazo carbonyl compounds under various catalytic conditions, including Rh(II) carboxylates, Cu(I) and Cu(II) complexes, PhCO(2)Ag/Et(3)N, TsOH, and SnCl(2).2H(2)O, has been investigated. It was found that, in most cases, the diazo decomposition gave preferentially 1,2-aryl migration product, but 1,2-hydride migration predominated when PhCO(2)Ag/Et(3)N was the catalytic system. Hammett correlation has been applied in the analysis of the electronic effects of 1,2-aryl migration. The factors that govern the migratory preference and the mechanistic aspects of the reaction are discussed.

First example of regiospecific intermolecular C-H insertion reactions of cyclic rhodium carbenoids: novel synthesis of 3-indol-3'-yloxindoles.

Facile regiospecific intermolecular C-H insertion reactions of cyclic rhodium carbenoids have been achieved using diazo carbonyl compounds 1 and indole or N-substituted indoles to afford 1,3-dihydro-1'H-[3,3']biindolyl-2-ones, 3a-o in an excellent yield.

Rh2(OAc)4-Catalyzed Regioselective Intermolecular C-H Insertion Reactions: Novel Synthesis of 2-Pyrrol-3′-yloxindoles

Regioselective synthesis of 2-pyrrol-3′-yloxindoles has been achieved by the reactions of cyclic diazo carbonyl compounds 1a-e with pyrrole and substituted pyrroles (2a-d) in the presence of rhodium(II) acetate catalyst via intermolecular C-H insertion reaction.

An Efficient Approach to α-Aryl β-Amino Esters through 1,2-Aryl Migration of p-Toluenesulfonic Acid Mediated Diazo Decomposition

A new method for the synthesis of α-aryl β-amino esters has been developed. The key step in this preparation is the chemoselective 1,2-aryl migration of diazo carbonyl compounds catalyzed by TsOH.

Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica

Diazocarbonyl compounds are a very important class of organic substances which have a long history of useful aplications in organic chemistry. The focus of this report deals with the use of diazocarbonyl compounds in a ariety of important reactions and their application in organic synthesis. These reactions are briefly summarized showing their broad scope.

Intramolecular C-H insertion reactions of (eta(5)-cyclopentadienyl)dicarbonyliron carbene complexes: scope of the reactions and application to the synthesis of (+/-)-sterpurene and (+/-)-pentalenene.

(eta(5)-Cyclopentadienyl)dicarbonyliron carbene complexes, [(eta(5)-C(5)H(5))(CO)(2)Fe=CHR](+)BF(4)(-), are generated as reactive intermediates from thioether derivatives, (eta(5)-C(5)H(5))(CO)(2)FeCH(R)SPh, by S-alkylation with trimethyloxonium tetrafluoroborate and loss of thioanisole. The carbene complexes undergo intramolecular C-H insertion into appropriately situated side chains to form cyclopentane derivatives. The reaction has been developed into a general procedure employing cycloalkanones as scaffolds bearing the iron carbene moieties and the side chains at C(2) and C(3), respectively. The products of the intramolecular insertion reactions are substituted bicyclo[n.3.0]alkanones. The scope and limitations of the reaction are described. The reaction is applied to a total synthesis of sterpurene and to a formal synthesis of pentalenene. Overall, this approach to cyclopentane annulation complements the related metal-catalyzed insertion reactions of diazocarbonyl compounds, which are also believed to occur via metal carbene complexes.

ChemInform Abstract: Reactions of Fluoroalkanesulfonyl Azides with Carbocyclic β-Keto Esters: Structural Influence of Dicarbonyl Substrate on Distribution of Diazo and Ring-Contraction Products.

Abstract The diazo transfer reactions of fluoroalkanesulfonyl azides 1 with ethyl 2-oxocyclopentanecarboxylate 2, in the presence of triethylamine, give ring-opened diazo amido esters 3a–3d in high yields. Rhodium-catalyzed decompositions of these novel diazocarbonyl compounds 3 have been examined. The results show that β-hydride elimination by an intermediate carbene or rhodium-carbenoid is exclusively preferred, and the intramolecular cyclization onto the N-sulfonylcarbamoyl substituent does not take place. However, when fluoroalkanesulfonyl azides 1 react with ethyl 2-oxocyclohexanecarboxylate 5, the ring-contraction product cyclopentanecarboxylate 6 is formed as the only product.

Reactions of fluoroalkanesulfonyl azides with carbocyclic β-keto esters: structural influence of dicarbonyl substrate on distribution of diazo and ring-contraction products

The diazo transfer reactions of fluoroalkanesulfonyl azides 1 with ethyl 2-oxocyclopentanecarboxylate 2, in the presence of triethylamine, give ring-opened diazo amido esters 3a– 3d in high yields. Rhodium-catalyzed decompositions of these novel diazocarbonyl compounds 3 have been examined. The results show that β-hydride elimination by an intermediate carbene or rhodium-carbenoid is exclusively preferred, and the intramolecular cyclization onto the N-sulfonylcarbamoyl substituent does not take place. However, when fluoroalkanesulfonyl azides 1 react with ethyl 2-oxocyclohexanecarboxylate 5, the ring-contraction product cyclopentanecarboxylate 6 is formed as the only product.

Facile construction of novel polycyclic ring systems using a metallocarbenoid-induced cyclization of acetylenic diazo carbonyl compounds

The Rh(II)-catalyzed reaction of diazo 2-propynyl maolonamic acid ester derivatives produce furo[3,4-c]furans in excellent yield. The methodology was applied to the synthesis of several polyheterocyclic systems by first generating a 2-alkoxy-substituted furan and then allowing it to undergo a subsequent intramolecular Diels-Alder cycloaddition. Ring opening of the resulting cycloadduct is followed by deprotonation to furnish a rearranged keto lactone.

Organophosphorus Compounds. Part 144: A Novel Approach to 1,3-Oxaphospholes from Phosphaalkynes and Isomünchnones

Phosphaalkynes 5 react with the isomünchnones 12 in a regiospecific process to furnish the 1,3-oxaphospholes 14. In contrast to other cycloadditions to isomünchnones, the bicyclic intermediate 13 cannot be detected in these reactions. It is not necessary to use isolated isomünchnones 12 for the synthesis of the 1,3-oxaphospholes. The reaction sequence is also successful by use of the diazocarbonyl compounds 11 and in situ generation of the isomünchnones therefrom.

Unusual formation of 7-vinylcycloheptatriene derivatives in the catalytic cyclopropanation of cyclooctatetraene with diazocarbonyl compounds in the presence of rhodium catalysts

The reaction of cyclooctatetraene with methyl diazoacetate or diazoacetone in the presence of rhodium binuclear complexes gives, besides 9-substituted bicyclo[6.1.0]nona-2,4,6-trienes (mixture ofanti- andsyn-isomers, total yields 60–75%), isomeric β-(cyclohepta-2,4,6-trien-1-yl)acrylates or 4-(cyclohepta-2,4,6-trien-1-yl)but-3-en-2-one in 20–34% yields. In the case of methyl diazoacetate, a mixture ofE- andZ-isomers in a ratio of −3.5∶1 was obtained, while diazoacetone gave onlyE-isomer.

ChemInform Abstract: Reactions of Monosaccharide Derivatives with Diazocarbonyl Compounds. Reactivity and Synthetic Applications.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Modern catalytic methods for organic synthesis with diazo compounds: from cyclopropanes to ylides

Synthesis of Alpha-Diazocarbonyl Compounds. Catalysts for Metal Carbene Transformations. Insertion Reactions. Intermolecular Cyclopropanation and Related Addition Reactions. Intramolecular Cyclopropanation and Related Addition Reactions. Cycloaddition and Substitution Reactions with Aromatic and Heteroaromatic Compounds. Generation and Reactions of Ylides from Diazocarbonyl Compounds. X-H Insertion Reactions of Diazocarbonyl Compounds (X = N,O,S,Se,P, Halogen). The Wolff Rearrangement and Related Reactions. Reactions of Alpha-Diazocarbonyl Compounds with Aldehydes and Ketones. Acid-Promoted Cyclization of Unsaturated and Aromatic Diazo Ketones. Miscellaneous Diazocarbonyl Reactions. Index.

Reactions of monosaccharide derivatives with diazocarbonyl compounds. Reactivity and synthetic applications

The reaction of monosaccharide derivatives with different stabilized diazo compounds is reported. Studies on the reactivity of the condensation products have been undertaken, finding out novel transfromations of β-oxy-α-diazo carbonyl compounds with sinthetic applications. Thus, a stereoselective Wolff rearrangement provided syn 2-hydroxy-1-methyl compounds, which represent macrolide type structural subunits. On the other hand, rhodium (II) mediated rearrangements of β-acetoxy-α-diazo carbonyl compounds derived from monosaccharides have led to an efficient synthesis of the natural aldonic acids KDG and DAH.

Asymmetric cyclopropanation of alkenes and diazocarbonyl insertion into SH bonds catalyzed by a chiral porphyrin Ru(II) complex

A homochiral porphyrin ruthenium(II) complex catalyzes the cyclopropanation of styrene derivatives with ethyl diazoacetate with good yields and moderate enantiomeric excesses (46–52 %). The catalyst is also active for diazocarbonyl compound insertion into SH bonds, but with low ee.

Synthesis of functionalised oxazoles and bis-oxazoles 1

A new method for the synthesis of oxazoles, and in particular chiral non-racemic oxazoles derived from amino acids, has been developed. Thus, rhodium(II) catalysed reaction of diazocarbonyl compounds 6 and 11 in the presence of amides 8 and 10 results in regioselective insertion of the carbenoid into the amide N–H bond with formation of the β-carbonyl amides 9 and 12. Cyclodehydration of amides 9 and 12 using triphenylphosphine–iodine–triethylamine gives functionalised oxazoles 7 and 13. The oxazoles 13c and 13f were converted into the bis-oxazoles 17a and 17b by a second rhodium(II) catalysed regioselective N–H insertion reaction on the amides 15, followed by cyclodehydration.

Catalytic asymmetric oxonium ylide - [2,3] sigmatropic rearrangement with diazocarbonyl compounds: First use of C 2-symmetry in Rh(II) carboxylates

Several new chiral rhodium(II) catalysts have been synthesised for evaluation as catalysts in asymmetric oxonium ylide-[2,3] sigmatropic rearrangement of diazocarbonyl substrates; a catalyst derived from ( S)- tert-leucine afforded a chiral benzofuranone derivative with an ee of 60 %.