Benziodoxoles as atom-transfer reagents

1-Me0 -MeC02C6H4, 1-MeO -BrC6H4,1,4-Me2CeH4, 1,3-Me2C6H4, MeOCeHs, Bu C6H5, AcOCeHs, naphthalene, 2,3-benzothiophene, etc. 

Azidobenziodoxole 102 (see Section 3.2.2.5) has been utilized as a reagent for efficient azidation of P-keto esters and sdyl enol ethers. The azidation of cyclic P-keto esters can be achieved in excellent yields in the absence of any catalyst. In the case of less reactive hnear p-keto esters and silyl enol ethers, complete conversion and good yields have been obtained using a zinc catalyst (2013OL3246). 

Azidations with azidobenziodoxoles can be effectively catalyzed by iron salts, such as iron(ll) propionate [Fe(02CEt)2]. In the presence of chiral oxazoline ligands (boxmi ligands), the Fe-catalyzed azidations of p-keto esters and oxindoles afford the respective a-azido-P-keto esters and 3-azidooxindoles with high enantioselectivity (up to 94% ee) (2013JA5356). 

An optimized procedure for the iron(II)-catalyzed azidations of tertiary C—FI bonds using azidobenziodoxole 104 has been reported by Sharma and Hartwig (2015NAT600). This reaction tolerates aqueous environments and is suitable for the functionalization of complex structures in the late stages of a multistep synthesis. 

This procedure has been appHed to the synthesis of N-cyanomethyl-N-cyclopropylamine, which is a possible metaboHte of cyclopropylamine-derived drugs (2001JA349). 

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