Silyl enol ethers Alkynyl groups

Belmont s group87 reported a cycloisomerization reaction on quinolines 77 (Scheme 5.34) bearing a silyl enol ether group on position 3 and an alkynyl group on position 2, leading to acridine derivatives 78. 

Matsuda and co-workers found that silyl enol ethers of thiol esters are good nucleophiles in the reaction with propargylic-type esters to form p-alkynyl thiol esters in the presence of a catalytic amount of [Ir(cod)(POPh3)2]OTf 32 [37]. The acetoxy group of 29 was readily substituted at 25 °C to form thiol ester 31 with 93% yield by simply stirring together 29,4 equiv of silyl enol ether 30, and 32 (5 mol%) (Eq. 16). 

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