Although high enantioselectivity of [2,3]-sigmatropic rearrangement of sulfonium ylides (Doyle-Kirmse reaction) has proven surprisingly elusive using classic chiral Rh(II) and Cu(I) catalysts, in principle it is due to the difficulty in fine discrimination of the heterotopic lone pairs of sulfur and chirality inversion at sulfur of sulfonium ylides.1 Here, we show that the synergistic merger of new α-diazo pyrazoleamides and chiral N,N'-dioxide-nickel(II) complex catalyst enables a highly enantioselective Doyle-Kirmse reaction. Pyrazoleamide substituent serves as both an activating and a directing group for the readily formation of metal-carbene and Lewis-acid bonded ylide intermediate2 in the assistant of dual tasking nickel(II) complex. These investigations shed light on several factors that directly impact the efficiency and enantioselectivity of Doyle–Kirmse reaction, enabling reasonable strategies for chirality transfer. The newly synthesized α-diazo pyrazoleamides and novel dual-functionality of N,N′-dioxide metal complex catalyst are likely to be instrumental in the success of future endeavors.

Chiral nickel(II) complex catalyzed enantioselective Doyle-Kirmse reaction of α-diazo pyrazoleamides

256th National Meeting (2018)

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