CHED 502 |
| As a versatile path to allyl vinyl ketone substrates for 6π-electrocylization reactions, the synthesis of 1-(isoxazolidin-2-yl)-2-(trimethylsilyl)prop-2-en-1-one was targeted as a key intermediate. The synthesis of the Weinreb-type urea (bis(N-methyl-O-methyl)hydroxylamine urea) was difficult to isolate by distillation in good yield as a high-boiling oil. A modified version of the urea using isoxazolidine as a N-methyl-O-methylhydroxylamine surrogate was designed to simplify purification and handling procedures. This crystalline bis(isoxazolidinyl) urea was produced using two different carbonyl sources: 1) triphosgene, and 2) 1,1'-carbonyldiimidazole. The latter reagent resulted in higher isolated product yield and observed purity. 13C NMR (CDCl3, 300 MHz) δ 165.4, 68.7, 48.7, and 28.3. Isoxazolidinyl amides and unsymmetrical ketones could then be synthesized using this urea precursor by stepwise organometallic addition reactions.
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Undergraduate Research Poster Session: Organic Chemistry
11:00 AM-1:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |