One-Pot O 2 -Oxidation and the Horner-Wadsworth-Emmons Reaction of Primary Alcohols for the Synthesis of ( Z )-α,β-Unsaturated Esters.

We developed one-pot oxidation/olefination procedures of primary alcohols giving Z -α,β-unsaturated esters 3 . TEMPO-(CuCl or CuBr 2 )-(2,2'-bipyridine) (1:1:1) catalyzed O 2 oxidation of primary alcohols in the presence of Z -selective Horner-Wadsworth-Emmons reagent 1b and K 3 PO 4 or NaH gave 3 with Z / E = 84:16 to 96:4 in high yields. A stepwise reaction was also developed. After TEMPO-CuBr 2 -(2,2'-bipyridine)-K 3 PO 4 (1:1:1:1) catalyzed O 2 oxidation of alcohols in MeCN, the resulting mixture was treated with a THF solution of 1b and t -BuOK at -78 °C to 0 °C, giving 3 with higher selectivity ( Z / E = 91:9 to 99:1).