Reactions of sodium selenide with ethynyl and bromoethynyl ketones: Stereo- and regioselective synthesis of functionalized divinyl selenides and 1,3-diselenetanes
摘要:
A method for the preparation of 2,4-dimethylene-1,3-diselenetanes based on the novel reaction of sodium selenide with bromoethynyl ketones has been developed. New functionalized divinyl selenides have been obtained by regio- and stereoselective addition of sodium selenide to ethynyl ketones. (C) 2009 Elsevier B. V. All rights reserved.
Stereoselective Synthesis of Trisubstituted Alkenes through Sequential Iron-Catalyzed Reductive<i>anti</i>-Carbozincation of Terminal Alkynes and Base-Metal-Catalyzed Negishi Cross-Coupling
作者:Chi Wai Cheung、Xile Hu
DOI:10.1002/chem.201504049
日期:2015.12.7
stereoselective synthesis of trisubstituted alkenes is challenging. Here, we show that an iron‐catalyzed anti‐selective carbozincation of terminal alkynes can be combined with a base‐metal‐catalyzed cross‐coupling to prepare trisubstituted alkenes in a one‐pot reaction and with high regio‐ and stereocontrol. Cu‐, Ni‐, and Co‐based catalytic systems are developed for the coupling of sp‐, sp2‐, and sp3‐hybridized
A new family of unnaturalaminoacids possessing a tetrahydroindole moiety is obtained by nucleophilic addition of various aminoacids to the triple bond of 2-benzoylethynyl-4,5,6,7-tetrahydroindoles. The reaction proceeds chemo-, regio- and stereospecifically in the presence of sodium hydroxide to give the Z-isomeric products in 35–72% yields. A new family of unnaturalaminoacids possessing a tetrahydroindole
Conjugate Addition to Acylketene Acetals Derived from 1,8-Dihydroxynaphthalene and Its Application To Synthesize the Proposed Structure of Spiropreussione A
作者:Hirokazu Tsukamoto、Yumi Nomura、Koichi Fujiwara、Shogo Hanada、Takayuki Doi
DOI:10.1021/acs.orglett.8b01259
日期:2018.5.18
A conjugate addition of diverse nucleophiles to acylketene acetals derived from 1,8-dihydroxynaphthalene (DHN) is developed for the formation of its 3-oxoalkan-1-one acetals. The initial acylketene acetals are prepared via double oxa-Michael addition of DHN to 1-bromo-1-propyn-3-ones. Carbonucleophiles, including organocopper reagents and active methylene compounds, and heteroatom nucleophiles were
Copper-Catalyzed Cross-Coupling of Vinylsiloxanes with Bromoalkynes: Synthesis of Enynes
作者:Loïc Cornelissen、Maxime Lefrancq、Olivier Riant
DOI:10.1021/ol501140p
日期:2014.6.6
of various sensitive enynes. The use of cis, trans, and 1,1′-disubstituted vinylsiloxanes was allowed, and full retention of stereochemistry was observed. Sensitive groups such as halides, unsaturated ketones, and aldehydes were fully tolerated.
The synthesis of heterocycles relies heavily on diverse sigmatropic rearrangements triggered by the cleavage of X–Y (X, Y = C, O, N, S, I) bonds. However, a unified rearrangement approach for constructing heterocyclic libraries is highly desirable. Encouraged by computational analysis of [3,3]-sigmatropic rearrangements, we can now rapidly synthesize oxa-heterocycles by treating N-phenoxyacetamides