Kung-Pern Wang

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Arynes generated directly from alkyne building blocks in the presence of silver catalysts effectively activate primary, secondary, and tertiary alkane C-H bonds. This C-H insertion requires only a catalytic amount of silver complex and modest heating compared to harsh conditions and extra promoters including directing groups, oxidants, and bases in typical(More)
The regioselectivity in nucleophile trapping is investigated with arynes generated directly from bis-1,3-diynes. The regioselectivity is profoundly influenced by not only the nature of nucleophiles but also the substituents on the arynes, which is the consequence of both the unfavorable steric interaction between the incoming nucleophile and the nearby(More)
The cross-metathesis of terminal alkyne and alkene using Ru-based Grubbs catalyst generally undergoes alpha-insertion. In this study, excellent control over alpha- and beta-insertion of ruthenium alkylidene into terminal alkynes has been achieved by using a substituent at a remote site from the reaction center. While the origin of this regioselectivity of(More)
A new functionalization method of arynes promoted by a novel catalytic role of the Grubbs-type ruthenium alkylidene complex is described. Through a sequence of aryne formation followed by their halo-functionalization, various bis-1,3-diynes were directly converted to functionalized aryl chlorides, bromides and iodides in good yields in the presence of a(More)
The isolation and structural characterization of alkyne-bound Ru alkylidene complexes has been elusive. However, a sequential enyne ring-closing metathesis of a diyne moiety and metallotropic [1,3]-shift followed by a second enyne ring-closing metathesis allowed the formation of a highly stable alkyne-chelated ruthenium complex. The full characterization of(More)
Invited for the cover of this issue are the groups of Yuanzhi Xia at Wenzhou University (P.R. China) and Daesung Lee at University of Illinois at Chicago (USA). The image depicts the mechanistic understanding of the regiodivergent cyclizations of- o-alkynylbenzaldehyde acetals and thioacetals catalyzed by metal halides. Read the full text of the article at(More)
An efficient 1,4-hydrovinylative cyclization reaction of triynes and tetraynes catalyzed by ruthenium alkylidene complexes under ethylene is described. The regioselectivity of vinyl group incorporation can be controlled by the nature of the substituent on the alkyne, and the Grubbs second-generation catalyst is the most effective among typical ruthenium(More)
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