Rhodium(I)‐Catalyzed Arylation/Dehydroxylation of <italic>tert</italic>‐Propargylic Alcohols Leading to Tetrasubstituted Allenes.

Abstract: Diverse tetrasubstituted allenes are obtained selectively by the reaction of <italic>tert</italic>‐propargylic alcohols and arylboroxines under rhodium catalysis. The reaction is assumed to proceed through an arylation/dehydroxylation process, which involves β‐hydroxide elimination of a β‐hydroxy alkenyl‐rhodium intermediate that is generated by regioselective arylrhodation of the <italic>tert</italic>‐propargylic alcohol. In addition, when enantioenriched propargylic alcohol was used to prepare optically active allene, high efficiency of central‐to‐axial chirality transfer was observed. The application of current method to structural modification of pharmaceutical drugs was also showcased by a highly diastereoselective transformation of mifepristone. [ABSTRACT FROM AUTHOR]