3,4-Diisopropoxy-3-cyclobutene-1,2-dione → 3-Isopropoxy-4-(tri-n-butylstannyl)-3-cyclobutene-1,2-dione

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Reaction Steps

A solution of 0.052M n-Bu4N+CN- in tetrahydrofuran (7.69 mL, 0.4 mmol) was added dropwise to a stirred solution at -20° C. of diisopropyl squarate (3.96 g, 0.020 mol) and n-Bu3SnSi(CH3)3 (7.27 g, 0.020 mol) in tetrahydrofuran (154 mL). Stirring was continued at -20° C. for 2 hrs. The solution was concentrated and the residue chromatographed on SiO2 with diethyl ether-hexane (10:90) to afford the title compound (5.75 g, 67% yield) as a yellow oil.

Provenance & Evidence