Diastereoselective Conjugate Additions to π-Allylmolybdenum Complexes: A Stereocontrolled Route to 3,4,5-Trisubstituted γ-Butyrolactones
2002; American Chemical Society; Volume: 4; Issue: 12 Linguagem: Inglês
10.1021/ol020043f
ISSN1523-7060
AutoresAnthony J. Pearson, Eugen F. Mesaros,
Tópico(s)Cyclopropane Reaction Mechanisms
Resumoπ-Allylmolybdenum complex 6b is obtained as a single isomer by Knoevenagel condensation of aldehyde 1 with Meldrum's acid. Conjugate additions of Grignard reagents to Meldrum's acid alkylidene derivative 6b are shown to be completely diastereoselective. Further functional group transformation of the 1,4-adducts, followed by demetalation, leads to trisubstituted tetrahydrofurans and γ-butyrolactones. Whereas the synthesis of tetrahydrofurans (X = 2H) is not completely stereoselective, the γ-butyrolactones (X = O) are obtained with good to excellent diastereoselectivities.
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