A comparative study of the decomposition of o-alkynyl-substituted aryl diazo ketones. Synthesis of polysubstituted .beta.-naphthols via arylketene intermediates
摘要:
The photochemical, thermal, and rhodium-catalyzed decomposition reactions of several closely related o-alkynyl or o-alkenyl alpha-diazoaceto- and propiophenone derivatives have been studied. The reaction outcome is markedly dependent upon the reaction conditions employed for nitrogen extrusion. Thermolysis or photolysis of o-alkynyl alpha-diazopropiophenone derivatives yields polysubstituted beta-naphthols. These products are derived from Wolff rearrangement of the initially formed carbene to give an aryl ketene which undergoes intramolecular cyclization onto the o-alkynyl substituent. In direct contrast to the thermal and photochemical results, Rh(II)-catalyzed decomposition yields products derived from direct attack of a rhodium carbenoid onto the tethered pi-system producing a vinyl carbenoid intermediate. Further reaction of the cyclized carbenoid with the starting diazo compound furnishes a vinyl indenone which undergoes a rapid intramolecular Diels-Alder reaction to produce a novel dimer whose structure was elucidated by an X-ray crystal analysis. Replacement of the methyl group on the diazo center with a sterically less demanding hydrogen atom was also found to play an important role in controlling the outcome of the Rh(II)-catalyzed reaction.
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.
Synthesis of spiro-compounds related to fredericamycin A
作者:Sharon M. Bennett、Derrick L. J. Clive
DOI:10.1039/c39860000878
日期:——
Spiro-compounds [e.g., (8), (13)] that resemble the four central rings of the antitumour agent fredericamycin A have been synthesized by methods that are based on (i) intramolecular acylation and high-pressure Diels–Alder chemistry [(5)→(8)] or (ii) radical spiro-cyclization [e.g., (11)→(13)].
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