Benzylic oxidation iodine catalyzed

Oxidative cyclization of benzyl and other 2-hydroxyethyl ethers to afford dioxolanes (Equation 46) can be achieved using A -iodosuccinimide in nitromethane for R = Ph <1998AGE3177> or photochemical reaction with iodine and polymer-supported iodobenzene diacetate in acetonitrile <2005SL923>. In a related process, RuCl2(Ph3P)2 catalyzes the isomerization of allyl 2-hydroxyethyl ether to form 2-ethyl-l,3-dioxolane <2004SL1203>. 

While the majority of Rh-catalyzed C-H amination processes employ hyperva-lent iodine oxidants and sulfonamide derivatives, Lebel and coworkers have demonstrated that /V-tosyloxycarbamates will engage with catalytic Rh2(02CCPh3)4 and K2CC>3 to afford products of intramolecular C-H insertion (Fig. 22) [104, 5, 105]. Similar to Du Bois earlier work involving oxidative cyclization with 1 ° carbamates [94], the /V-tosyloxy derivatives display a strong bias for oxazolidinone formation. Selectivity trends and other mechanistic data support a reaction pathway involving a Rh-nitrene oxidant. Intermolecular amination of simple benzylic substrates... 

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