Science of Synthesis

Palomo, C.; Aizpurua, J. M., Science of Synthesis, (2006) 23, 233.

Multiple C—C 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 Bellus–Claisen [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.

‌Meeeee 88‌ Meeeeee Meeeee–Meeeeee Meeeeeeeeeeee ee Meeeeeeeeeeeeeeee eeee ee Meeeeee Meeeeee[‌88‌]

Me eeeeeeeeee eeeeeeeeeee ee eee eee-Meeeeee eeeeeeeeeeeee ee eeeeeee M-eeeeeeeeeee eeeeeeeeeee eeeeeeee e eeeeeee eeeeeee eeeeee.[‌88‌] Me eeee eeee, eeeeeee, eee eeeeeeeeee ee eee eeeeeeeeeee eeeee ee ee eeeeeeee ee eeeeeeeee eee eeeeeeeeeeeeee ee eeee eeeeee, eee eeeeeee eeeeeeeee α-eeeee eeee eeeeeeeee eee eeee ee eeeeeeee eeeeee eeeeeee.

Meeeeeeeeeee Meeeeeeee

(8M*,8M*,8M*)-8,8-Meeeeeeeeee-8-ee-8,8-eeeeeeeeeeeee-8-eeeeee-8-eeeeeeeeeeeeeeee-8,8-eeeee (‌88‌):[‌88‌]

Mee eeeeeee eeeeeee ‌88‌ (888 ee, 8.888 eeee ) eee MM8Me8 (88 eM), eeeeeeee ee eMe8MMe (8.88 eM, 8.8 eeee), eeee eeeee ee e eeeee eeeeeeeeee Me(MMe)8 (888 ee, 8.888 eeee) ee 88°M. Meeee 8 eee, e 8 M eeee ee eee eeee eeeeeeee ‌88‌ (8.8 eM, 8.8 eeee) ee MM8Me8 (8 eM) eee eeeee eeeeeeee eeeeee 8 eee. Mee eeeeeeeee eeee eee eeee eee eeeeeeeeee ee 88°M eeeee eee eeeeee ‌88‌ eee eeeeeeee (8–8 e), ee eeeeeeeeee ee MMM (MeMMe). Mee eeeeeee eee eeee eeeeeee eeee MeMMe (88 eM) eee eeeeee eeee 8 M ee MeMM (88 eM). Mee eeeeeee eeeee eee eeeeeeeee eeee MeMMe (8 × 88 eM), eee eee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee, eeeee (Me8MM8), eee eeeeeeeeeeee ee eeeee. Mee eeeeeeeee eeeee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, MeMMe) ee eeee e eeeee eeeeee eeeee; eeeee: 888 ee (88%); (eee,eeee/eeee,eeee) 88:8.

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