Tributylvinyltin → HCID 90449481, compound

The 1-(2-(trimethylsilyl)ethyl) 1′-tert-butyl 5-bromospiro[indoline-3,3′-pyrrolidine]-1,1′-dicarboxylate (1.00 g, 2.01 mmol) obtained in Step 2 of Example 383 was dissolved in tetrahydrofuran (20 mL). Thereafter, tributyl(vinyl)tin (1.40 mL, 4.79 mmol), tetrakistriphenylphosphine palladium (240 mg, 0.21 mmol), and lithium chloride (260 mg, 6.13 mmol) were added to the above obtained solution at room temperature, and the thus obtained mixture was then stirred for 21 hours while heating under reflux. Thereafter, the reaction solution was purified by silica gel column chromatography (hexane:ethyl acetate=10:1) to obtain 1-(2-(trimethylsilyl)ethyl) 1′-tert-butyl 5-vinylspiro[indoline-3,3′-pyrrolidine]-1,1′-dicarboxylate (723 mg, 81%) in the form of a light yellow solid.