17592-40-4Relevant articles and documents
Modular Synthesis of α-Substituted Alkenyl Acetals by a Palladium-Catalyzed Suzuki Reaction of α-Haloalkenyl Acetals with Organoboranes
Zhang, Li
, p. 723 - 727 (2021/02/26)
A modular and straightforward synthetic strategy for the preparation of α-substituted alkenyl acetals has been developed. α-Haloalkenyl acetals react smoothly with (het)aryl boronic acids, aryl boronates, or B-Alkyl-9-borabicyclo[3.3.1]nonanes through Pd-catalyzed Suzuki cross-coupling under mild conditions with good to high yields. This protocol features a broad substrate scope and good functional-group compatibility, and is easily scaled up.
Formal synthesis of Aspidosperma alkaloids via the intramolecular [3 + 2] cycloaddition of 2-azapentdienyllithiums
Pearson, William H.,Aponick, Aaron
, p. 1661 - 1664 (2007/10/03)
A formal synthesis of the Aspidosperma alkaloids aspidospermidine, aspidospermine, and quebrachamine is reported through an efficient preparation of Stork's penultimate intermediate. The key step of the sequence involved an intramolecular [3 + 2] cycloaddition of the 2-azapentadienyllithium 21 formed in situ from the corresponding imine 1, which after N-alkylation of the resulting cycloadduct provided 2 in excellent yield. The synthesis represents a new disconnection of the classical tricyclic ketone used for appendage of the requisite indole.
1-Bromo-2-ethoxycyclolithium: A Synthetic Equivalent of 2-Lithio or 3-Lithiopropenal. Application to the Synthesis of Juvenile Hormone (JH-II), β-Sinensal, and Jasmonoids.
Morizawa, Yoshitomi,Kanakura, Akihiro,Yamamoto, Hajime,Hiyama, Tamejiro,Nozaki, Hitosi
, p. 1935 - 1942 (2007/10/02)
The ethyl vinyl ether-dibromocarbene adduct was lithiated with butyllithium at -95 deg C in tetrahydrofuran.The resulting lithium carbenoid 3 was allowed to react with various electrophiles to give 1-substituted trans-1-bromo-2-ethoxycyclopropanes (1) in good yields.The trans relationship of Br and OEt groups was found particularly pertinent to the ethanolysis of 1 producing 2-substituted propenal diethyl acetal derivatives.The reaction has been applied to 1-methoxycyclohexene-dibromocarbene adducts, giving rise hereby 2-substituted 2-cyclohepten-1-one dimethyl acetals under ring enlargement.T he transformation has been utilized in the synthesis of a homoterpenoid (JH-II) or a terpenoid (β-sinensal) structure by SN2' substitution of allylic acetates with lithium dimethylcuprate(I) or iron pentacarbonyl respectively.The reaction products of 3 with aldehydes are oxidized with dimethyl sulfoxide to give cyclopropyl ketones whose ethanolysis in the presence of boron trifluoride ether complex gives β-bromo γ-keto aldehyde acetals.Debromination followed by acidic hydrolysis produces γ-keto aldehydes serving as precursors of dihydrojasmone and cis-jasmone.
