Aryl derivatives terminal acetylene synthesis

Some multicomponent syntheses of trisubstituted oxazoles were described. a-Isocyano-a-alkyl(aryl)acetamides, as 131 <05S161>, was demonstrated to be a useful starting material for a three-component reaction involving isoquinoline 129 <05SL532>. A four-component synthesis was also published starting from an aldehyde, a silylamide, an acyl chloride and a terminal acetylene derivative. The overall process is a modification of a four-component synthesis of a propargylic amide 134 which can be eventually isolated <05T 11317>. 

Another efficient method to prepare chiral propargylamines 42 using a multicomponent process is by alkylation of in situ formed propargyl imines from alkynals 40 and o-phenoxy aniline (11c) by dialkylzinc derivatives 41 in the presence of a chiral ligand, for instance a dipeptide, and a Lewis acid salt, as depicted in Scheme 11.16 [48], Furthermore, the synthesis of A-aryl propargyl amines can be also performed by the alkynylation using dimethylzinc and terminal acetylenes of several aldehydes and o-methoxyaniline catalyzed by (l/ ,25)-A-bis(p-methoxybenzyl)norephedrine and phenylacetylene (52-93%, 79-97% ee) [49],... 

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