Palladium catalysis cyclisation reactions

Scheme 7.72 Tandem a-aminooigrlation or -amination-reductive cyclisation reaction catalysed by chiral amine catalysis and palladium catalysis.

Another cyclisation involving 4-amino-6-methyl-3-thioxo-l,2,4-tiiazin-5-one 82 is the reaction with propargyl bromide followed by palladium(II) catalysis to yield a [1,2,4] triazino[3,4-f ][l,3,4]thiadiazine 83, or with phenacyl bromide to give 84 <96MI03 96CA(125)195597 96MI04 96CA(125)247767 >. 

Insertion of palladium vinyls derived from 30 into tethered alkynes leads to 31. In the presence of alkenes, or appropriate pendant unsaturated functions, rearrangemrat to 32 and spontaneous cyclisation take place. These reactions therefore constitute efficient routes to arene or diene > containing, or completely saturated - tricyclic systems under PdL2 catalysis. If the geometry of 32 is unfavourable or prevented completely diverse products can arise, including cyclopropanes. 52... 

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