69754-58-1Relevant academic research and scientific papers
SYNTHESE D'ALCOHOLS α-ALLENIQUES PAR REACTION D'ORGANOCHROMIQUES PROPARGYLIQUES SUR LES ALDEHYDES ET LES CETONES
Place, Pierre,Verniere, Catherine,Gore, Jacques
, p. 1359 - 1368 (1981)
Propargylic bromides can be condensed with aldehydes and ketones in the presence of Hiyama's reagent (2CrCl3+LiAlH4 in THF) leading to α-allenic alcohols, to homopropargylic alcohols or to the mixture of both of them.The selectivity (or specificity) of this reaction depends on the substitution of the propargylic bromide, on the structure of the ketone, and on the presence of HMPT in the reaction mixture.In many cases, α- allenic alcohol has been specifically or very selectively obtained.The mechanism of the reaction and the influence of the various parameters are discussed.
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.
