Cp2ZrCl2-Catalyzed cycloalumination of acetylenic alcohols and propargylamines by Et3Al
作者:I. R. Ramazanov、R. N. Kadikova、U. M. Dzhemilev
DOI:10.1007/s11172-011-0013-2
日期:2011.1
The Cp2ZrCl2-catalyzed cycloalumination of acetylenic alcohols and propargylamines by Et3Al was studied. The process affords 2,3-disubstituted alumacyclopent-2-enes, which were identified by the analysis of the products of their deuterolysis and hydrolysis. The cycloalumination of alkyl- and phenyl-substituted propargylamines proceeds with high regio- and stereoselectivity to give the corresponding allylamine derivatives in high yield. Unlike the phenyl derivatives, the cycloalumination of alkyl-substituted acetylenic alcohols (propargyl, homopropargyl, and bishomopropargyl alcohols) is not regioselective.
Copper-Catalyzed Highly Regio- and Stereoselective Directed Hydroboration of Unsymmetrical Internal Alkynes: Controlling Regioselectivity by Choice of Catalytic Species
Taking control of boron: A highly regio‐ and stereoselective copper‐catalyzedhydroboration of unsymmetrical internal alkynes has been developed. The regioselectivity was successfully controlled by the choice of catalytic species (copper hydride or boryl copper; see scheme).
Titanium(IV) isopropoxide and ethylmagnesium bromide catalyzed reaction of 2-alkynylamines with Et2Zn, followed by deuterolysis/hydrolysis and iodinolysis, affords substituted (Z)-pent-2-en-2,5-d 2-1-amines, (Z)-pent-2-en-1-amines (65–88%), and substituted (Z)-2,5-diiodopent-2-en-1-amines (55–63%). It is suggested that the reaction proceeds through the formation of cyclic organotitanium derivatives. The
Mild and efficient synthesis of propargylamines by copper-catalyzed Mannich reaction
作者:Lothar W. Bieber、Margarete F. da Silva
DOI:10.1016/j.tetlet.2004.09.079
日期:2004.11
Terminal alkynes undergo mild and efficient aminomethylation with aqueous formaldehyde and secondary amines under CuI catalysis. In most cases high to nearly quantitative yields of tertiary propargylamines are obtained in DMSO solution at room temperature. Aromatic, aliphatic and silylated acetylenes as well as alkynols can be used. Primary amines are less reactive and satisfactory yields of secondary propargylamines
The reaction of diiodomethane and triethylaluminum with substituted 1-alkenylaluminums obtained by the Zr-catalyzed carbo- or cycloalumination of mono- or dialkyl-substituted alkynes resulted in the selective formation of di- and tetrasubstituted cyclopropanes. 1-Alkenylaluminums prepared from substituted propargylamines reacted with diiodomethane and triethylaluminum to give substituted allylamines