Carbonylation of Propargyl Carbamates with Palladium(II) Bisoxazoline Catalysts: Efficient Synthesis of 5-Methoxy-3(2H)-furanones


  • This work was supported by a Grant-in-Aid for Scientific Research (C) (No. 24590026).


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Palladium and CO: Carbonylation of 1 with [Pd(tfa)2(±)-L1] (tfa=trifluoroacetate) affords the spirofuranone 2 with inversion of the stereochemistry at C17 in 96 % yield. C17-epi-1 also gave the same product 2 with retention of the stereochemistry at C17. Labelling studies show that 13CO was incorporated into the C5′ position of the furanone ring. The first asymmetric version of this new reaction was achieved.