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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). Nanyang Technological University We gratefully acknowledge the financial support from Nanjing Tech University (Start-up grant nos. 39837118, 39837101, and 39837146), the SICAM Fellowship from Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Forestry University, and Nanyang Technological University. more...

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. more...

An efficient diastereoselective allylation of various carbonyl compounds with cyclic allylic halides by using commercially available bismuth powder in the presence of LiI was developed. Among all the metals screened, bismuth was found to be the best mediator for the transformation. The reactions involving various cyclic allylic halides proceeded smoothly at room temperature to produce the desired homoallylic alcohols in good to excellent yields with high diastereoselectivities (>99:1 dr). Reversed diastereoselectivity was obtained when carbonyl substrate (e. g., 2-pyridinecarboxaldehyde, glyoxylic acid) containing chelating substituent was used in the allylation reaction. In addition, the reactions involving acyclic (E)-cinnamyl bromide as substrate worked equally well with high diastereocontrol. (Figure presented.). Nanyang Technological University We gratefully acknowledge the financial support from Nanj-ing Tech University (Start-up Grant No. 39837118, 39837101,and 39837146), the SICAM Fellowship from Jiangsu NationalSynergetic Innovation Center for Advanced Materials, Post-graduate Research&Practice Innovation Program of JiangsuProvince (No. KYCX18_1075), and Nanyang Technological University.t more...

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. more...

An efficient iron-mediated highly diastereoselective allylation of carbonyl compounds with cyclic allylic halides is reported. The allylation reactions involving various carbonyl compounds proceeded efficiently in the presence of 20 mol% bismuth(III) chloride to give the corresponding homoallylic alcohols in moderate to good yields with excellent diastereoselectivities and wide functional group tolerance. In cases where an aldehyde and a ketone (e.g., 2-pyridinecarboxaldehyde and phenylglyoxylic acid) containing an adjacent chelating atom were used, complete reversal of product diastereoselectivities was observed which could be explained by the Cram-chelated six-membered ring transition state. Nanyang Technological University We gratefully acknowledge the financial support from Nanjing Tech University (Start-up Grant No. 39837118, 39837101, and 39837146), the SICAM Fellowship from the Jiangsu National Synergetic Innovation Center for Advanced Materials, Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. KYCX18_1075), and Nanyang Technological University. more...