Editorial [Hot topic: Novel Chiral Catalysts for Enantioselective Alkynylation Reactions (Guest Editor: Jincheng Mao)]

During the past decades, great progress has been made on the direct asymmetric addition of terminal alkynes to carbonyl compounds (aldehydes and ketones) and imines. The present issue is focused on the recent development of novel chiral catalysts for such enantioselective alkynylation reactions. Asymmetric alkynylation of imines is reviewed by Prof. Pedro. Diastereoselective procedures are involved in the addition of metal alkynylides to chiral nonracemic imines derived from chiral amines or chiral carbonyl compounds. Enantioselective non-catalytic procedures have been achieved with the use of stoichiometric additives or alkynylboron reagents. In addition, catalytic addition of terminal alkynes or zinc acetylides has been carried out in the presence of chiral metal complexes, especially copper complexes as catalysts. The second review has been provided by Dr. Tyrrell on the topic of asymmetric alkynylation reaction of aldehydes by a Zn(OTf)2-chiral ligand-base system. It demonstrates the synthetic utility of effective Carreira’s protocol in an array of natural product synthesis. In the past several years, various combinations of novel chiral ligands and transition metal sources have been employed as catalysts in organozinc reagents mediated asymmetric alkynylation reaction. In the review by Prof. Mao and et al., they highlight the recent advances in this field and try to compare the methods available for this transformation.