Pivalic acid → ethyl (S)(E)-2-{2-[2-(4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl)ethylidene]cyclopent-1-yl}acetate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of (S)-2-(4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl)-1-cyclopentenyl-1-hydroxyethane (2.8 g), pivalic acid (0.1 g) and triethyl orthoacetate (125 ml) was heated to 138° C. After 2.5 hours, more pivalic acid (65 mg) was added and the reaction was continued 1 hour more. The reaction mixture was cooled, the excess triethyl orthoacetate removed/n vacuo, and the residue chromatographed on silica gel (20% ethyl acetate/hexane) to give ethyl (S)(E)-2-{2-[2-(4-t-butyldimethylsilyloxy-1,3-dihydro-6-ethyl-7-methyl-3-oxoisobenzofuran-5-yl)ethylidene]cyclopent-1-yl}acetate.

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