325. F. Romanov-Michailidis, L. Guénée, A. Alexakis,
     “Enantioselective Organocatalytic Iodination-Initiated Wagner-Meerwein Rearrangement”
     Org. Lett. 2013, 15, 5890-5893.

The present manuscript describes a high-yielding enantioselective semipinacol transposition, initiated by an electrophilic iodination event. The title transformation makes use of the anionic phase-transfer catalysis (PTC) paradigm for chirality induction. Thus, when combined appropriately, the insoluble cationic iodinating reagent S₉ and the lipophilic phosphoric acid L₉ act as an efficient source of chiral iodine that performs the semipinacol transposition of strained allylic alcohols A_x to β-iodo spiroketones B_x in good yields and with high levels of diastereo- and enantio-induction. The product β-iodo spiroketones could be derivatized stereospecifically and without stereoerosion, giving rise to products inaccessible directly from a semipinacol rearrangement.

DOI : 10.1021/ol402981z 

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