The First Catalytic Carbonylative [4 + 1] Cycloaddition Using a 1,3-Conjugated System. A New Transformation of α,β-Unsaturated Imines to Unsaturated γ-Lactams Catalyzed by Ru₃(CO)₁₂

The First Catalytic Carbonylative [4 + 1] Cycloaddition Using a 1,3-Conjugated System. A New Transformation of α,β-Unsaturated Imines to Unsaturated γ-Lactams Catalyzed by Ru3(CO)12</sub

Utilization of Aldoses as a Carbonyl Source in Cyclocarbonylation of Enynes

The reaction of enynes with acetyl-masked aldoses in the presence of a rhodium(I) catalyst resulted in cyclocarbonylation, thus avoiding the direct use of carbon monoxide, to afford bicyclic cyclopentenones. In rhodium catalysis, aldoses serve as a carbon monoxide equivalent by donating their carbonyl moieties on the acyclic aldehyde form to enynes. A variety of aldoses, including d-glucose, d-mannose, d-galactose, d-xylose, and d-ribose, can be used as a carbonyl source. Using the method, a wide variety of enynes were cyclocarbonylated in 22−67% yields. An asymmetric variant also proceeded with moderate to high enantioselectivity

Carbonylative [5 + 1] Cycloaddition of Cyclopropyl Imines Catalyzed by Ruthenium Carbonyl Complex

Carbonylative [5 + 1] Cycloaddition of Cyclopropyl Imines Catalyzed by Ruthenium Carbonyl Comple

CO-Transfer Carbonylation Reactions. A Catalytic Pauson−Khand-Type Reaction of Enynes with Aldehydes as a Source of Carbon Monoxide

The reaction of enynes with aldehydes in the presence of a catalytic amount of [RhCl(cod)]2/dppp results in the Pauson−Khand-type reaction without the use of gaseous carbon monoxide to give bicyclic cyclopentenones in high yields (14 examples). Aldehydes serve as a source of carbon monoxide, and their carbonyl moiety is transferred to enynes, resulting in the formation of the carbonylated products. This reaction represents the first example of a CO-transfer carbonylation

Ru₃(CO)₁₂-Catalyzed Cyclocarbonylation of Yne-Aldehydes to Bicyclic α,β-Unsaturated γ-Butyrolactones

Ru3(CO)12-Catalyzed Cyclocarbonylation of Yne-Aldehydes to Bicyclic α,β-Unsaturated γ-Butyrolactone

Site-Selective Conversion of Azido Groups at Carbonyl α‑Positions to Diazo Groups in Diazido and Triazido Compounds

This paper reports on the selective conversion of alkyl azido groups at the carbonyl α-position to diazo compounds. Through β-elimination of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl moieties were transformed into α-diazo carbonyl groups in one step. As these reaction conditions do not involve aryl or general alkyl azides, site-selective conversions of di- and triazides were achieved. Through this method, the successive site-selective conjugation of the triazido molecule with three different components is demonstrated

Site-Selective Conversion of Azido Groups at Carbonyl α‑Positions to Diazo Groups in Diazido and Triazido Compounds

This paper reports on the selective conversion of alkyl azido groups at the carbonyl α-position to diazo compounds. Through β-elimination of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl moieties were transformed into α-diazo carbonyl groups in one step. As these reaction conditions do not involve aryl or general alkyl azides, site-selective conversions of di- and triazides were achieved. Through this method, the successive site-selective conjugation of the triazido molecule with three different components is demonstrated

Correction to “Photodissociation of the Product from a Transition-Metal Center Allows the Catalytic Cycle to Proceed: The Rhodium(I)-Catalyzed [2+2+1] Carbonylative Cycloaddition of Diynes”

Correction to “Photodissociation of the Product from a Transition-Metal Center Allows the Catalytic Cycle to Proceed: The Rhodium(I)-Catalyzed [2+2+1] Carbonylative Cycloaddition of Diynes

Regioselective Rapid Synthesis of Fully Substituted 1,2,3-Triazoles Mediated by Propargyl Cations

Regioselective rapid triazole syntheses at low temperature are described. Organic azides and propargyl cations generated by acids gave fully substituted 1<i>H</i>-1,2,3-triazoles. Most reactions could be performed in 5 min at not only rt but also −90 °C. Both terminal and internal alkynes were acceptable, and the sterically bulky substituents could afford the products smoothly. Various types of three-component coupling reactions were demonstrated, and the presence of allenylaminodiazonium intermediates was indicated

Iridium(I)-Catalyzed Cycloisomerization of Enynes

Iridium(I)-Catalyzed Cycloisomerization of Enyne