Unexpected Formation of a Chiral spiro‐system in the Reaction of the Dilithium Derivative of Hexafluorocumyl Alcohol with N‐(t–butylsulfenyl)phthalimide

Abstract

An unexpected course of the reaction of hexafluorocumyl alcohol dilithium derivative 2 with N‐(t‐butylsulfenyl)phthalimide (3) has been presented. The process proceeded under mild conditions and resulted in previously undescribed chiral spiro‐system – 3',3'‐bis(trifluoromethyl)‐3H,3'H‐1,1'‐spirobis(isobenzofuran)‐3‐one (5) as the only product. A detailed spectral analysis of the product has been provided, and mechanistic aspects have been investigated. Attempts to separate the enantiomers of compound 5 using a semipreparative HPLC method with a chiral stationary phase column have been described. The repeatability of the reaction using analogs of alcohol 4 has also been tested. DFT calculations of absolute configuration assignment have been performed successfully.