Spiro compounds spirocyclopropanes

Another interesting approach to the synthesis of spiro compounds incorporating a cyclopropane was developed by Lattanzi and coworkers. In this work, a-bromo-methylmalonate reacted with 2-arylidene-l,3-indandiones 86 to afford the corresponding spirocyclopropanes 87 in good to excellent yields (74-96%) and moderate to good enantioselectivities (60-85%) when the diarylprolinol derivative XXI was used as the catalyst [50] (Scheme 10.30). 

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