One‐Pot Dual C−C Coupling Reaction via Site Selective Cascade Formation by Pd^II‐Cryptate of an Amino‐Ether Heteroditopic Macrobicycle

Abstract

Selectivity of aryl iodo over ethynyl iodo toward the Suzuki cross coupling reaction is explored by utilizinga palladium complex of amino-ether heteroditopic macrobicycle. Subsequently,u nreacted ethynyl iodide undergoes ho-mocoupling reactioni nt he same catalytic atmosphere, therebyr epresenting ac ascade dual CÀCc oupling reaction. Furthermore, this approach is extended for novel one-pot synthesis of unsymmetrical 1,3-diynes.

One‐pot synthesis of unsymmetrical 1,3‐butadiyne derivatives

“…Subsequently, a large number of methods for the direct synthesis of unsymmetric1,3-enynes have been reported in the literature, such as Cu(I) catalyzing the cross-coupling reaction between alkynyl chlorides and alkynyl silanes, 27 Pd-catalyzed cross-coupling reaction of alkynyl iodines with alkynyl stilles was developed for the synthesis of unsymmetric 1,3-enynes, 28 Ni-catalyzed cross-coupling of acetylenic sulfones and alkynyl Grignard reagents, 21 the unsymmetric 1,3-enynes was successfully synthesized by Fe /Cu co-catalyzed alkynyl bromide and pinacol ester of alkynyl boronic acid in the presence of dimethyl carbonate, 29,30 using Ni(acac) 2 as catalyst and DPPE as ligand to catalyze organic aluminum and alkyl halides in dimethyl ether solution, the unsymmetric 1,3-diynes product was successfully obtained, 30,31 etc. Although transition-metal (Cu, Ni, Fe, Pd) catalyzed tandem reactions of alkynyl element-organic complexes (Mg, B, Al, Si, Sn) play a crucial role because of their efficient and selective properties (Schemes 1, 1-c); however, the substrates are expensive and often require prefunctionalization of special alkynyl halogen, which increased production costs.…”