Rhenium-Catalyzed Regio- and Stereoselective Synthesis of γ‑Thio-α,β-unsaturated Ketones via Insertion of Terminal Alkynes into the C–S Bond

The reaction of α-thioketones and alkynes in the presence of a rhenium catalyst, [HRe(CO)₄]_<i>n</i>, gave γ-thio-α,β-unsaturated ketones in excellent yields. The alkynes were inserted into the carbon–sulfur bond of the α-thioketones, and isomerization of a double bond provided the products with high regio- and stereoselectivities. This reaction also proceeded in an intramolecular fashion

Rhenium-Catalyzed Synthesis of 2<i>H</i>‑1,2-Oxaphosphorin 2‑Oxides via the Regio- and Stereoselective Addition Reaction of β‑Keto Phosphonates with Alkynes

Treatment of β-keto phosphonates (Horner–Wadsworth–Emmons reagents) with terminal alkynes in the presence of a rhenium catalyst gave 2<i>H</i>-1,2-oxaphosphorin 2-oxides with various substitution patterns. The reaction proceeds via two consecutive processes: cleavage of a carbon–carbon σ-bond of the β-keto phosphonate with insertion of the alkyne in a regio- and stereoselective manner, followed by cyclization of the resulting δ-phosphonyl α,β-unsaturated ketone yielding the 2<i>H</i>-1,2-oxaphosphorin 2-oxide. Horner–Wadsworth–Emmons reagents were found to add to nonpolar unsaturated compounds under neutral conditions

Rhenium-Catalyzed Regio- and Stereoselective Synthesis of γ‑Thio-α,β-unsaturated Ketones via Insertion of Terminal Alkynes into the C–S Bond

The reaction of α-thioketones and alkynes in the presence of a rhenium catalyst, [HRe(CO)₄]_<i>n</i>, gave γ-thio-α,β-unsaturated ketones in excellent yields. The alkynes were inserted into the carbon–sulfur bond of the α-thioketones, and isomerization of a double bond provided the products with high regio- and stereoselectivities. This reaction also proceeded in an intramolecular fashion

Amine-Promoted <i>anti</i>-Markovnikov Addition of 1,3-Dicarbonyl Compounds with Terminal Alkynes under Rhenium Catalysis

Amines have been identified to greatly accelerate the intermolecular <i>anti</i>-Markovnikov addition of carbon nucleophiles to unactivated terminal alkynes. Using a combination of [ReBr­(CO)₃(thf)]₂ and ^<i>i</i>Pr₂NEt, construction of cyclic all-carbon quaternary centers was achieved with various 1,3-ketoesters, diketones, and diesters with lower catalyst loading under milder conditions. The type of addition could be easily controlled by choice of additive, highlighting the unique features of rhenium catalysi

Bismuth(III)-Catalyzed Dehydrative Etherification and Thioetherification of Phenolic Hydroxy Groups

Use of a bismuth catalyst allowed efficient dehydrative substitution of phenolic hydroxy groups with alcohols and thiols to form C–O and C–S bonds. The reaction required equimolar amounts of two readily available substrates that generated H₂O as the only byproduct. The relatively mild reaction conditions were compatible with the functional groups selected, and provided excellent chemoselectivity

Synthesis of Linear Allylsilanes via Molybdenum-Catalyzed Regioselective Hydrosilylation of Allenes

A simple molybdenum-based catalytic system for hydrosilylation of allenes has been developed. The reactions of mono- and disubstituted allenes with secondary and tertiary silanes proceeded smoothly and selectively to afford linear allylsilanes. The origin of the unprecedented linear selectivity was investigated by density functional theory studies to reveal that the reaction consists of the following steps: (1) concerted hydromolybdation/Si–H oxidative addition from a Mo­(CO)₄/allene/silane adduct to form (π-allyl)­molybdenum, (2) allyl rotation from the initially formed (π-allyl)­molybdenum to a thermodynamically more stable isomer, and (3) reductive elimination at the less-hindered allyl carbon to afford a linear allylsilane

Rhenium-Catalyzed Regio- and Stereoselective Synthesis of γ‑Thio-α,β-unsaturated Ketones via Insertion of Terminal Alkynes into the C–S Bond

The reaction of α-thioketones and alkynes in the presence of a rhenium catalyst, [HRe(CO)₄]_<i>n</i>, gave γ-thio-α,β-unsaturated ketones in excellent yields. The alkynes were inserted into the carbon–sulfur bond of the α-thioketones, and isomerization of a double bond provided the products with high regio- and stereoselectivities. This reaction also proceeded in an intramolecular fashion

Correction to Palladium-Catalyzed Synthesis of Dibenzophosphole Oxides via Intramolecular Dehydrogenative Cyclization

Correction to Palladium-Catalyzed Synthesis of Dibenzophosphole Oxides via Intramolecular Dehydrogenative Cyclizatio

Rhenium-Catalyzed <i>anti</i>-Markovnikov Addition Reaction of Methanetricarboxylates to Unactivated Terminal Acetylenes

A novel <i>anti</i>-Markovnikov addition reaction of methanetricarboxylates with terminal acetylenes under neutral conditions was achieved using a rhenium complex. This transformation represents a rare example of intermolecular <i>anti</i>-Markovnikov addition of carbon nucleophiles to unactivated terminal acetylenes. 1,3-Diesters having bulky substituents at the active methylene carbon are also applicable as substrates to provide <i>anti</i>-Markovnikov adducts as single regio- and stereoisomers. Preliminary mechanistic studies imply that the rhenium vinylidene species is the key intermediate in the current catalytic cycle

Rhenium-Catalyzed Regio- and Stereoselective Synthesis of γ‑Thio-α,β-unsaturated Ketones via Insertion of Terminal Alkynes into the C–S Bond

The reaction of α-thioketones and alkynes in the presence of a rhenium catalyst, [HRe(CO)₄]_<i>n</i>, gave γ-thio-α,β-unsaturated ketones in excellent yields. The alkynes were inserted into the carbon–sulfur bond of the α-thioketones, and isomerization of a double bond provided the products with high regio- and stereoselectivities. This reaction also proceeded in an intramolecular fashion