Replacement of HMPA in Samarium Diiodide Promoted Cyclizations and Reactions of Organolithium Compounds

Tripyrrolidinophosphoric acid triamide (TPPA) can replace carcinogenic HMPA as a Lewis basic additive in many reactions involving samarium ketyls. In most cases, yields and selectivities of cyclizations of (het)aryl, alkenyl, and alkynyl ketones are similar. TPPA is also a good substitute of HMPA in the O‐silylation of an ester enolate and in reactions oflithiated 1,3‐dithiane. All these results clearly demonstrate that in many cases the use of HMPA can be avoided.