Reaction Mechanism

edit

The α-haloester undergoes single electron transfer with zinc dust 1 and rearranges to eliminate the halide 3. Another single electron transfer occurs and the resulting ion 4 coordinates to zinc metal. The oxygen on an aldehyde or ketone also coordinates to the zinc to form the six-member chair like transition state 5. A rearrangement occurs in which zinc switches to the aldehyde or ketone oxygen and a carbon-carbon bond is formed 6. Acid workup removes zinc 7,8 to yield ZnX2 (zinc(II)) and a β-hydroxy-ester 9. [1]

 
  1. ^ Kurti, L.; Czako, B. ‘‘Strategic Applications of Named Reactions in Organic Synthesis’’; Elsevier: Burlington, 2005.