ABSTRACT
The copper(II)-mediated ring opening/alkynylation of cyclopropanol by employing inexpensive and commercially available terminal alkyne is developed. The reactions proceeded efficiently to afford synthetically useful alk-4-yn-1-ones in moderate to good yields with good functional group tolerance. Control experiments showed that the reaction presumably proceeds via the formation of intermediates of copper homoenolate and/or alkynylcopper species.
ABSTRACT
Lead was found to efficiently mediate the allylation reactions of carbonyl compounds with cyclic allylic halides in the presence of stoichiometric amounts of lithium chloride and a catalytic amount of GaCl3 (20 mol %), leading to the desired homoallylic alcohols in modest to high yields with excellent diastereocontrol (>99:1 syn/anti) and good functional group tolerance. In contrast, the use of either 2-pyridinecarboxaldehyde as the carbonyl substrate or ( E)-cinnamyl bromide as the allylating agent produced the corresponding product with reversed diastereoselectivity (>99:1 anti/syn).
ABSTRACT
An efficient copper-catalyzed three-component cyclization for the construction of highly functionalized pyrimidine derivatives from readily available amidines, styrenes and fluoroalkyl halides is developed. This protocol distinguishes itself by the formation of three new C-C/C-N bonds and a new six-membered ring through a radical addition/oxidation/cyclization sequence in a one-pot manner.
