35281-64-2Relevant academic research and scientific papers
Theoretical support for the involvement of a radical pathway in the formation of allenylzincs from propargyl iodides and dialkylzincs: Influence of zinc coordination
Jammi, Suribabu,Mouysset, Dominique,Siri, Didier,Bertrand, Michèle P.,Feray, Laurence
, p. 1589 - 1603 (2013/04/10)
Propargyl iodides are good precursors for allenylzincs via reaction with diethylzinc, even in nondegassed medium. These reactions proceed via zinc/iodine exchange. Owing to the previously reported detection of propargyl radical by ESR experiments, in this process a radical mechanism was suspected. Calculations of the C-Zn BDEs in allenyl- and propargylzinc species were performed with the CBS-QB3 method to demonstrate that propargyl radicals could undergo homolytic substitution at zinc. The stabilization of allenylzinc derivatives by chelation, made possible by the selection of appropriate ortho-substituted 3-phenylalkynyl iodides as precursors, was shown to influence the regioselectivity of their addition to aldehydes and ketones. The more stabilized the chelated allenylzinc intermediate, the higher the ratio of homopropargylic alcohols.
An efficient CuCN-catalyzed synthesis of optically active 2,3-allenols from optically active 1-substituted 4-chloro-2-butyn-1-ols
Li, Jing,Kong, Wangqing,Fu, Chunling,Ma, Shengming
supporting information; experimental part, p. 5104 - 5106 (2009/10/17)
(Chemical Equation Presented) The sequential treatment of optically active terminal propargylic alcohols with n-BuLi/(HCHO)n and regioselective chlorination afforded the corresponding optically active 4-chloro-2-butyn-1-ols. With R1
Studies on Cu(I)-catalyzed synthesis of simple 3-substituted 1,2-allenes and optically active 2-substituted secondary 2,3-allenols
Li, Jing,Zhou, Chao,Fu, Chunling,Ma, Shengming
experimental part, p. 3695 - 3703 (2009/09/05)
The sequential treatment of terminal alkynes or propargylic alcohols with n-BuLi and MOMCl afforded the corresponding propargylic methyl ethers, which would react with primary alkyl Grignard reagents under the catalysis of CuBr to afford 3-substituted 1,2-allenes or 2-substituted secondary 2,3-allenols, respectively. The reaction may be applied to the synthesis of optically active 2-substituted secondary 2,3-allenols with up to >99% ee without any protection to the free hydroxyl group in the starting 4-hydroxy-2-alkynyl methyl ethers.
Selective Propargylation of Carbonyl Compounds with Allenylstannane/Alkyllithium Mixed Reagents
Suzuki, Masaaki,Morita, Yasushi,Noyori, Ryoji
, p. 441 - 449 (2007/10/02)
1-Substituted allenyltrialkylstannanes readily undergo transmetalation with an alkyllithium to generate a tetraalkylstannane and an equilibrating mixture of the allenyl- and propargyllithium compounds.The organolithium derivatives react with a variety of aldehydes and ketones at low temperature to give, after aqueous workup, the regioisomeric acetylenic and allenic carbinols in high yields.The degree of the regioselection is highly sensitive to the steric and electronic properties of the carbonyl substrates.Excellent acetylene selectivities are obtainable by combination of the bulky reagents and substrates or by using acylsilanes as carbonyl components.The origin of the regioselectivity is discussed.
Propargyl and Allyl Grignard and Zinc Reagents. Regioselective Alkylation and Its Application to the Synthesis of PGE3 and F3α Methyl Ester
Yanagisawa, Akira,Habaue, Shigeki,Yamamoto, Hisashi
, p. 5198 - 5200 (2007/10/02)
Regioselective propargylation and allylation were achieved using acylsilanes as electrophiles, and this methodology was applied to the synthesis of PGE3 and F3α methyl ester.
