Vinylogous Barbier reaction

Vinylogous Barbier reaction,4 Smlj (2 equiv.) can effect cyclization of the unsaturated iodo ketone 1 in THF containing DMPU (or HMPA) to give a bicyclic samarium enolatc (a) that can be trapped by an aldol reaction. 

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See also in sourсe #XX -- [ ]

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