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Directed Metalation of Ester-Substituted Indolizines
Directed Metalation of 1-Ester-Substituted Indolizines: Base/Electrophile-Controlled Regioselective Functionalization.
Org. Lett. 2015;
16 February 2015 (online)
Clososki and co-workers report a directed C–H functionalization of 1-ester-substituted indolizines using several organometallic bases. The metalation takes place under mild conditions, and the reaction with different electrophiles allows the synthesis of a number of polyfunctional indolizines in good yields.
Lithium amides favor C-5 functionalization, while TMPMgCl·LiCl gives C-2 substituted derivatives as major products by ortho metalation. The authors found that in the case of functionalization with TMPMgCl·LiCl, the reactivity of the electrophile plays a key role in the regioselectivity of the reaction.