Benzaldehyde with vinyllithium

Lithium-tellurium exchange generation of vinyllithium (typical procedure). Method A. To a solution of butyl vinyl telluride (0.211 g, 1 mmol) in THF (4 mL) at -78°C under N2 is added dropwise a solution of n-BuLi (1.5 M in hexane, 0.67 mL, 1 mmol). After stirring for 40 min at -78°C, benzaldehyde (0.016 g, 1 mmol) is added. The mixture is allowed to react at room temperature for 30 min, diluted with EtOAc (40 mL) and washed with brine. 

The two modifications described above have allowed for the efficient capture of vinyllithium intermediates generated in Shapiro reactions with a wide variety of electrophiles. For example, the alkyllithium reagent 20 prepared from treatment of trisylhydrazone 18 with n-BuLi was effectively trapped with benzaldehyde (62% yield, 21), 1 -bromobutane (58% yield, 22), and bromine from 1,2-dibromoethane (43% yield, 23)." Similarly, formation of 20 from tosylhydrazone 19 followed by trapping with CO2 afforded 24 (52% yield). The reaction of intermediate 20 (generated from 19) with cyclohexenone provided 25, the product of 1,2-addition, in 61% yield.13... 

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