PhI(OCOCF3)2-Mediated Cyclization of o-(1-Alkynyl)benzamides: Metal-Free Synthesis of 3-Hydroxy-2,3-dihydroisoquinoline-1,4-dione
摘要:
The synthesis of an undocumented skeleton of 3-hydroxy-2,3-dihydroisoquinoline-1,4-diones has been discovered and reported. The reaction consists of an intramolecular cyclization of o-(1-alkynyl)benzamides in MeCN/H2O, mediated by metal-free, hypervalent reagent of PhI(OCOCF3)(2), followed by an oxidative hydroxylation reaction: The mechanism consisting of two pathways has been proposed and discussed:
Reaction of 2-Alkynylbenzoyl
Cyanides with Carboxylic Acids Producing Functionalized Indenones
作者:Masahiro Murakami、Hiroshi Shimizu
DOI:10.1055/s-2008-1078501
日期:——
2-Alkynylbenzoyl cyanides react with carboxylic acidsvia a cyclicallene intermediate to produce 2-acylamino-3-acylindenones in good yield. The high reactivity of the 2-acylamino moiety of the product for a substitution reaction can be utilized for the synthesis of fused heterocycles.
An efficient and catalytic protocol for highlystereoselective construction of β-mannopyranosylation has been developed. Glycosylation of 2,6-lactone-bridged mannopyranosyl ortho-hexynylbenzoate with various acceptors proceeded smoothly in the presence of 5% Hg(II) at room temperature, resulting in the corresponding β-mannosides in high yield and exclusive β-stereoselectivity.
Copper(II)/DBU Relay Catalyzed Annulation of α-Carbonyl-γ-alkynyl Sulfoxonium Ylides for Accessing <i>N</i>-Sulfonamido 2<i>H</i>-Isoindoles
作者:Peng Zhou、Wei-Tao Yang、Wen-Juan Hao、Bo Jiang
DOI:10.1021/acs.orglett.3c03479
日期:2023.12.1
A copper(II)/DBU relay catalyzed annulation of α-carbonyl-γ-alkynyl sulfoxonium ylides as a new class of sulfoxonium ylide reagents with sulfonyl hydrazides is reported, enabling intramolecular oxygen migration to produce a series of N-sulfonamido 2H-isoindoles with good yields. The present annulation proceeded readily by combining the Cu(II)-catalyzed 6-endo-dig oxo-cyclization with the DBU-catalyzed
Intramolecular Carboxyamidation of Alkyne‐Tethered <i>O</i>‐Acylhydroxamates through Formation of Fe(III)‐Nitrenoids
作者:Siyuan Su、Yu Zhang、Peng Liu、Donald J. Wink、Daesung Lee
DOI:10.1002/chem.202303428
日期:2024.1.26
induced spontaneous or 4-(dimethylamino)pyridine-catalyzed O→O or O→N acyl group migration can generate a wide variety of N,O-containing heterocycles. DFT study suggests the Fe-nitrenoid intermediate preferentially reacts in a radical manifold to mediates a stepwise C−N/C−O bond formation rather than a concerted [3+2] cycloaddition mechanism.
Zip and shift : 炔烃束缚的O-酰基异羟肟酸酯的分子内羧酰胺化,然后是热诱导自发或4-(二甲氨基)吡啶催化的O→O或O→N酰基迁移,可以生成多种含N 、 O的杂环。 DFT 研究表明,Fe-氮烯类中间体优先在自由基流形中反应,介导逐步的 C−N/C−O 键形成,而不是协调一致的 [3+2] 环加成机制。