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DOI: 10.1055/sos-SD-023-00175

Palomo, C.; Aizpurua, J. M.Science of Synthesis, (200623233.

Multiple CC bond-forming stereoselective reactions involving aminoketenes are useful for constructing relatively complex chemical structures of the carbon-tethered α-amino carbonyl type. For instance, 2 equivalents of the ketene obtained by dehydrochlorination of phthalimidoacetyl chloride 30 with N,N-diisopropylethylamine react stereoselectively with the allylic diamine 39 in the presence of 2 equivalents of ytterbium(III) trifluoromethanesulfonate to provide the BellusClaisen [3,3]-rearrangement[‌66‌] double adduct 41 containing the 3-substituted 2,6-diamino-1,7-dioxoheptane framework (Scheme 12).[‌67‌,‌68‌] The high stereoselectivity observed during the formation of the three new stereocenters can be rationalized by assuming that the rearrangements of 39 to 40 and of 40 to 41 proceed via the chair-like transition states 42 and 43, respectively.

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