Protecting Groups Cleaved by Transition Metal Catalysis

2 11 Protecting Groups Cleaved by Transition Metal Catalysis 

For allyl ethers, rearrangement of the double bond to the more thermodynamically stable enol ether can be accomplished using tris[triphenylphosphine]rho-dium(l) chloride (Wilkinson s catalyst). A possible mechanism for the rhodium(I)- 

For allyl ethers that are stable to strong base, deprotection can be accomplished by a two step process involving isomerisation of the double bond of the allyl group using potassium /err-butoxide in DMSO. The resultant enol ether is a stable intermediate that can then be hydrolysed with mild acid as in the case of the rhodium(I)-catalysed isomerisation.  

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