13524-09-9Relevant academic research and scientific papers
Copper-Catalyzed Asymmetric Silylation of Propargyl Dichlorides: Access to Enantioenriched Functionalized Allenylsilanes
Liu, Zheng-Li,Yang, Chao,Xue, Qi-Yan,Zhao, Meng,Shan, Cui-Cui,Xu, Yun-He,Loh, Teck-Peng
supporting information, p. 16538 - 16542 (2019/11/11)
A copper-catalyzed silylation of propargyl dichlorides was developed to access chloro-substituted allenylsilanes under mild reaction conditions. Moreover, enantioenriched chloro-substituted allenylsilanes can be synthesized in moderate to high yields and good enantioselectivities with this protocol.
Copper-Catalyzed Propargylic Substitution of Dichloro Substrates: Enantioselective Synthesis of Trisubstituted Allenes and Formation of Propargylic Quaternary Stereogenic Centers
Li, Hailing,Grassi, David,Guénée, Laure,Bürgi, Thomas,Alexakis, Alexandre
supporting information, p. 16694 - 16706 (2016/02/12)
An easy and versatile Cu-catalyzed propargylic substitution process is presented. Using easily prepared prochiral dichloro substrates, readily available Grignard reagents together with catalytic amount of copper salt and chiral ligand, we accessed a range of synthetically interesting trisubstituted chloroallenes. Substrate scope and nucleophile scope are broad, providing generally high enantioselectivity for the desired 1,3-substitution products. The enantioenriched chloroallenes could be further transformed into the corresponding trisubstituted allenes or terminal alkynes bearing all-carbon quaternary stereogenic centers, through the copper-catalyzed enantiospecific 1,1/1,3-substitutions. The two successive copper-catalyzed reactions could be eventually combined into a one-pot procedure and different desired allenes or alkynes were obtained respectively with high enantiomeric excesses.
Copper-catalyzed enantioselective synthesis of axially chiral allenes
Li, Hailing,Mueller, Daniel,Guenee, Laure,Alexakis, Alexandre
supporting information, p. 5880 - 5883 (2013/02/23)
A simple copper-catalyzed enantioselective synthesis of axially chiral chloroallenes from the propargylic dichlorides is reported, employing a catalytic amount of easily prepared SimplePhos ligand. Exclusive formation of the desired allenes was observed with good enantioselectivities (ee's 62-96%). Further transformations to trisubstituted allenes or terminal alkynes with a propargylic quaternary carbon center keep a high level of enantiopurity.
ALKYNYLHALOCARBENES. 2. GENERATION OF (ALKYN-1-YL)CHLOROCARBENES BY BASIC SOLVOLYSIS OF 1,1-DICHLORO-2-ALKYNES AND THEIR REACTION WITH OLEFINS: SYNTHESIS OF 1-CHLORO-1-ALKYNYLCYCLOPROPANES
Shavrin, K. N.,Krylova, I. V.,Dolgii, I. E.,Nefedov, O. M.
, p. 885 - 891 (2007/10/02)
1,1-Dichloro-2-alkynes R1CCCHCl2 (4a-g: R1=Me, n-Pr, c-Pr, t-Bu, Ad, Nor, Ph) were synthesized with yields of 50-75percent by chlorination with PCl5 of formylacetylenes (3a-g), prepared by oxidation of propargyl alcohols (1a-d) with CrO3*Py*HCl complex or acidolysis of propargyl acetals (2a-c) in the presence of catalytic quantities of pyridine; the corresponding alkynylchlorocarbenes, R1CCCCl (5a-g) were generated from them with powdered KOH in a two-phase system or t-BuOK. The latter were trapped by olefins with formation of 1-chloro-1-alkynylcyclopropanes (6a-t) with yields of up to 90percent.Keywords: alkynylchlorocarbenes, 1,1-dichloro-2-alkynes, basic solvolysis, interphase catalysis, 1-chloro-1-alkynylcyclopropanes.
Alkynylhalocarbenes: Generation from 1,1-Dihaloalk-2-ynes by Base Solvolysis and Reaction with Alkenes
Shavrin, Konstantin N.,Krylova, Irina V.,Shvedova, Inna B.,Okonnishnikova, Galina P.,Dolgy, Igor E.,Nefedov, Oleg M.
, p. 1875 - 1882 (2007/10/02)
A series of 1,1-dihaloalk-2-ynes 1-3 has been prepared by halogenation of the formylacetylenes 8 with PCl5 or an equimolar mixture of PCl5 and Br2.A simple, general means of access to the alkynylhalocarbenes 5 has been developed via base-initiated α-elimination of 1,1-dihalo-2-ynes (1-3).The carbenes 5a-i have been trapped by alkenes, to form 1-alkynyl-1-halocyclopropanes (11) in up to 90percent yield.Under the same conditions compound 1g was converted into the butadiene 12.Experimental evidence for the electrophilicity and the singlet nature of carbenes 5 has been obtained.
