Fu-Yu Tsai

A reusable FeCl3·6H2O/cationic 2,2′-bipyridyl catalytic system for the coupling of aryl iodides with thiols in water under aerobic conditions

In this study, an FeCl3·6H2O/cationic 2,2′-bipyridyl system was employed as a catalyst in the coupling of aryl iodides with thiols to form an aryl–sulfur bond in refluxed water under aerobic conditions. The residual aqueous solution after extraction could be reused for several cycles without a significant decrease in activity.

Homocoupling reaction of terminal alkynes catalyzed by a reusable cationic 2,2′-bipyridyl palladium(II)/CuI system in water

A cationic 2,2′-bipyridyl palladium(II)/CuI system was proven to be a reusable and highly efficient catalyst for the homocoupling of terminal alkynes at room temperature using water as a solvent in the presence of TBAB under aerobic conditions. For aromatic terminal alkynes, the reaction was performed either with or without I2 as an oxidant; the addition of I2 was required when aliphatic terminal alkynes were used as a substrate for the homocoupling reaction. In the presence of 0.0001–1 mol% palladium catalyst and 1 mol% CuI, a variety of terminal alkynes were homocoupled in good to excellent yields. The water-soluble catalytic system was separated from the organic products by extraction and the residual aqueous solution showed activity for reuse for several cycles without a significant decrease in activity.

Sonogashira Reaction of Aryl and Heteroaryl Halides with Terminal Alkynes Catalyzed by a Highly Efficient and Recyclable Nanosized MCM-41 Anchored Palladium Bipyridyl Complex

A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further runs without significant loss of reactivity.

Reusable and efficient CoCl2 ·6H2O/cationic 2,2’-bipyridyl system-catalyzed S-arylation of aryl halides with thiols in water under air

A CoCl2·6H2O/cationic 2,2’-bipyridyl system was proven to be an efficient and reusable catalyst for the coupling of aryl halides with thiols in water under aerobic conditions, leading to the formation of thioethers. Aryl iodides and bromides could couple with various thiols giving the corresponding thioethers using only a 3 mol% catalyst loading in the presence of 1 equiv KOH and 1.5 equiv Zn at 100 °C. For aryl chlorides, reaction at 140 °C and prolongation of the reaction time was performed. After reaction, the residual aqueous solution could be reused several times without any additional treatment and regeneration, making this cobalt-catalyzed S-arylation reaction greener.

Palladium(II)/Cationic 2,2’-Bipyridyl System as a Highly Efficient and Reusable Catalyst for the Mizoroki-Heck Reaction in Water

A water-soluble and air-stable Pd(NH3)2Cl2/cationic 2,2’-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu3N as a base. The reaction was conducted at 140 °C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated aryl iodides with butyl and ethyl acrylates, providing the corresponding products in good to excellent yields with very high turnover numbers. In the case of styrene, Mizoroki-Heck coupling products were obtained in good to high yields by using a greater catalyst loading (1 mol %) and TBAB as a phase-transfer agent. After extraction, the residual aqueous solution could be reused several times with only a slight decrease in its activity, making the Mizoroki-Heck reaction “greener”.

A new stable intermediary mode between η3-2-aminoallyl complexes and metallacyclobutanimines. Synthesis and structural characteristic of η3-azatrimethylenemethane and N-protonated, N-alkylated, N-arylated η3-azatrimethylenemethane complexes of Pt and Pd

Regioselective addition of ammonia, primary or secondary amines, aniline, or amino derivatives either to a neutral ( η 1 -allenyl)platinum complex trans -Pt(Br)(PPh 3 ) 2 ( η 1 -CHCCH 2 ) ( 1 ) or to a cationic η 3 -allenyl/propargyl platinum complex [Pt(PPh 3 ) 2 ( η 3 -C 3 H 3 )](BF 4 ) ( 2 ) provide the synthesis of cationic N -protonated, N -alkylated, and N -arylated η 3 -azatrimethylenemethane complexes {Pt(PPh 3 ) 2 ( η 3 -CH 2 C(NRR′)CH 2 ]}(X) (R=H R′=H ( 3a ), Me ( 3b ), Et ( 3c ), i Pr ( 3d ), t Bu ( 3e ), c-C 6 H 11 ( 3f ), Ph ( 3g ), CH 2 CH 2 OH ( 3h ), R=R′=Et ( 3i ), c-C 3 H 6 (from azetidine 3j ), Ph ( 3k ), R=Me R′=Ph ( 3l ); X=Br, BF 4 ), respectively. Addition of amides to 1 gave a neutral η 3 -azatrimethylenemethane complex Pt(PPh 3 ) 2 [ η 3 -CH 2 C(NSO 2 Ph)CH 2 ] ( 4m ). Similar reactions using palladium complexes yield {Pd(PPh 3 ) 2 [ η 3 -CH 2 C(NRR′)CH 2 ]}(X) (R=H R′= i Pr ( 7d ), Ph ( 7g ), R=R′=Et ( 7i ); X=Br, BF 4 , OTf), Pd(Br)(PPh 3 )[ η 3 -CH 2 C(NEt 2 )CH 2 ] ( 8i ) and Pd(PPh 3 ) 2 [ η 3 -CH 2 C(NR)CH 2 ] (R=SO 2 Ph ( 9m ), p -SO 2 C 6 H 4 Me ( 9n )). Synthesis of three complexes, {M(PPh 3 ) 2 [ η 3 -CH 2 C(NHR)CH 2 ]} + (M=Pt R=SO 2 Ph ( 3m ); M=Pd R=SO 2 Ph ( 7m ), p -SO 2 C 6 H 4 Me ( 7n )), can not be done by hydroamination reactions, but has been successful using protonation of η 3 - N -TMM complexes 4m , 9m , and 9n , respectively. Spectroscopic and crystallographic characterizations indicate that these N -TMM complexes exhibit intermediary structural features between η 3 -2-aminoallyl and metallacyclobutanimine complexes. 2

Constituents of Polyalthia longifolia var. pendula

Three new clerodane-type diterpenes, 6alpha,16-dihydroxycleroda-3,13-dien-15-oic acid (1), 6alpha,16-dihydroxycleroda-4(18),13-dien-15-oic acid (2), and 4alpha,18beta-epoxy-16-hydroxyclerod-13-en-15-oic acid (3), and four new protoberberine alkaloids, (-)-8-oxo-10-hydroxy-2,3,9-trimethoxyberberine (4), (-)-8-oxo-2,11-dihydroxy-3,10-dimethoxyberberine (5), (-)-8-oxo-11-hydroxy-2,3,9,10-tetramethoxyberberine (6), and (-)-8-oxo-2,10-dihydroxy-3,9,11-trimethoxyberberine (7), together with 11 known substances, were isolated from a methanol extract of the stems of Polyalthia longifolia var. pendula. The structures of 1-7 were elucidated on the basis of spectroscopic data analysis. Compounds were evaluated for their antiproliferative activities against A549 and MCF-7 cancer cells, and among the substances tested, only 16-oxo-cleroda-3,13-dien-15-oic acid (8) exhibited cytotoxicity.

Controlled Regiodivergent C–H Bond Activation of Imidazo[1,5-a]pyridine via Synergistic Cooperation between Aluminum and Nickel

The catalytic method features a cooperative interaction between Ni and Al imparting remote C-H alkenylation at the C5 position of imidazo[1,5-a]pyridine with alkynes at mild conditions. Exclusion of AlMe3 switches the selectivity to the C3 position. Reactions with styrene and other olefinic substrates affording C5-adducts by Ni/Al catalysis are also included.

HALOGEN-DEPENDENT COUPLING REACTION OF ALKYNES WITH (Z)-3-HALOPROPENOATES CATALYZED BY NICKEL

Abstract Ni-catalyzed coupling reaction of alkynes with ( Z )-3-halopropenoates depended on the halogen of halopropenoates. The reaction with ( Z )-3-bromopropenoate afforded cyclopentadienes and the reaction with ( Z )-3-iodopropenoates gave pyrones.

Regioselective addition of chalcogenol to an η3-propargyl/allenyl complex via formation of the carbon-chalcogen bond leading to new chalcogenoxyallyl species☆

Regioselective addition of chalcogenol to an ν3-propargyl complex Pt(PPh3)2(η3-C3H3)](BF4) (2) via the formation of the CO, CS, or CSe bond generates new cationic chalcogenoxyallyl species {Pt(PPh3)2[η3CH2C(ER)CH2]}(BF4) (E = O, R = Me 4(a), Et (4b, iPr (4c), 1Bu (4d), Ph (4e); ES, EEt (5b), tBu (5d, Ph (5e); ESe, RPh (6e )) respectively in good yields. Thiol and selenol react with complex 2 much faster than alcohol; and 2 reacts with p-(HO)C6H4(SH) to exclusively yield the thioxyallyl product {Pt(PPh3)2[η3-CH2C(SC6H4OH)CH2]}(BF4) (5f). Among the alcoh and phenol, thereactivity follows the order MeOH > EtOH >, iPrOH >, tBuOH > PhOH. A mechanism comprising a preceding coordination step is postulated. The X-ray structures of 4b, 4e, 5b, 5e and 6e are provided.