Multicomponent Cascade Cycloaddition Involving Tropone, Allenoate, and Isocyanide: A Rapid Access to a 7,6,5-Fused Tricyclic Skeleton

Multicomponent cascade cycloaddition of tropone, allenoate, and isocyanide has been disclosed. This method allows for the rapid construction of a highly unusual tricyclic skeleton in an efficient manner. The proposed transformation proceeds through [8 + 2 + 1] cycloaddition, [1,5]-H shift, and cyclization followed by an alkoxy group migration process

Fragments of 'Systema morborum'

Unprecedented aryne Diels–Alder reactions by using methyleneindolinones as dienes have been disclosed, thus providing a quick access to unusual naphtho-fused oxindoles. A wide range of methyleneindolinones proceed readily with arynes to afford the functionalized oxindoles in good yields

AlCl₃‑Promoted Selective Michael Addition with Allenoate and Methyleneindolinone: Synthesis of Spirocyclic Oxindole by Using Allenoate as a Four-Carbon Component Building Block

The AlCl₃-promoted cyclization of readily available allenoates with methyleneindolinone is disclosed. The present strategy provides a rapid access to spirocyclic oxindole-cyclohexenones in an efficient manner. Remarkably, the allenoate is implemented as a four-carbon (4C) component to form the ring, which shows high synthetic efficiency. Flexibility of this method allows quick synthesis of spirocyclic oxindole-dihydropyrans by varying one of the components. It is also noteworthy that AlCl₃ serves as the chlorine source as well as an effective catalyst to facilitate this interesting transformation

Construction of Naphtho-Fused Oxindoles <i>via</i> the Aryne Diels–Alder Reaction with Methyleneindolinones

Unprecedented aryne Diels–Alder reactions by using methyleneindolinones as dienes have been disclosed, thus providing a quick access to unusual naphtho-fused oxindoles. A wide range of methyleneindolinones proceed readily with arynes to afford the functionalized oxindoles in good yields

AlCl₃‑Promoted Selective Michael Addition with Allenoate and Methyleneindolinone: Synthesis of Spirocyclic Oxindole by Using Allenoate as a Four-Carbon Component Building Block

The AlCl₃-promoted cyclization of readily available allenoates with methyleneindolinone is disclosed. The present strategy provides a rapid access to spirocyclic oxindole-cyclohexenones in an efficient manner. Remarkably, the allenoate is implemented as a four-carbon (4C) component to form the ring, which shows high synthetic efficiency. Flexibility of this method allows quick synthesis of spirocyclic oxindole-dihydropyrans by varying one of the components. It is also noteworthy that AlCl₃ serves as the chlorine source as well as an effective catalyst to facilitate this interesting transformation

Temperature-Dependent Double Isocyanide Insertion Reaction To Construct a Polycyclic Skeleton

A novel strategy to furnish selective double insertion of isocyanides with the aid of potassium tetrachloroaurate­(III) has been disclosed. This strategy provides quick access to approach a complex polycyclic skeleton in an efficient manner. Unexpected oxygen migration was also observed when the reaction was conducted at a lower temperature

Multiple Stimuli-Responsive Conformational Exchanges of Biphen[3]arene Macrocycle

Conformational exchanges of synthetic macrocyclic acceptors are rather fast, which is rarely studied in the absence of guests. Here, we report multiple stimuli-responsive conformational exchanges between two preexisting conformations of 2,2&prime;,4,4&prime;-tetramethoxyl biphen[3]arene (MeBP3) macrocycle. Structures of these two conformations are both observed in solid state, and characterized by 1H NMR, 13C NMR and 2D NMR in solution. In particular, conformational exchanges can respond to solvents, temperatures, guest binding and acid/base addition. The current system may have a role to play in the construction of molecular switches and other stimuli-responsive systems

Palladium-Catalyzed Synthesis of Δ²‑Isoxazoline from Toluene Derivatives Enabled by the Triple Role of Silver Nitrate

A palladium-catalyzed direct synthesis of Δ²-isoxazoline from toluene derivatives has been established. The present reaction proceeds through nondirected Csp³–H activation, benzylic nitration, dehydration, and cycloaddition. This protocol also features the unusual triple role of silver nitrate in a one-pot reaction

Selective and Effective Binding of Pillar[5,6]arenes toward Secondary Ammonium Salts with a Weakly Coordinating Counteranion

The selective and effective binding of secondary ammoniums with a weakly coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF) counteranion by per-ethylated pillar[5,6]arenes is reported. The construction of a first pillararene-based self-sorting system consisting of two wheels and two axles is also described

Indium(III) Chloride-Catalyzed Isocyanide Insertion Reaction to Construct Complex Spirooxindole

An unusual multiple isocyanide insertion reaction with methyleneindolinone using indium­(III) chloride as the catalyst has been disclosed. This strategy allows for the rapid construction of structurally complex spirooxindole in an efficient manner. The present protocol features mild conditions, atom economy, and broad substrate scope