The present invention is a novel intermediate, compound of the formula (VI)
1
and salts thereof. In addition, the invention includes a process for the preparation of a prostaglandin intermediates compounds (IV) and (XVIII) which comprises (1) contacting a the corresponding enone with (-)-chlorodiisopinocampheylborane while maintaining the reaction mixture temperature in the range of from about −
50
° to about
0
° and (2) contacting the reaction mixture of step (1) with a boron complexing agent.