Electron, Transfer from Metal Surfaces. Formation of Lithium and Grignard Reagents1

Chiral (+)‐(S)‐4‐methylcyclohexylidenebromomethane (1) has been prepared from (−)‐(R)‐4‐methylcyclohexylideneacetic acid by a stereospecific bromode‐carboxylation reaction. The reaction was shown to proceed with an overall inversion of configuration. The reaction of the chiral vinyl bromide with lithium and magnesium metal surfaces produced the corresponding chiral vinyllithium and Grignard reagents. The mechanism of formation of these reagents will be discussed.