In another example, Oda et al. have utilized an acid-catalyzed lactonization of a
δ-hydroxy amide derivative in the synthesis of insect pheromone 12 [43]
(Scheme 7). The condensation of the diacid dichloride derived from keto diacid
39, with (R)-(+)-[1,1
0 -binaphthyl]-2,2
0 -diamine, afforded the coupled product 41,
)
)
Scheme 1 Pappo and Jung synthesis of δ-lactones
Scheme 2 Heathcock and Chavdarian synthesis of δ-lactones
Scheme 3 Coke and Richon synthesis of the proposed pheromone from Vespa orientalis
Scheme 4 Paterson and Khan synthesis of δ-lactones
Scheme 5 Yamaguchi et al. synthesis of δ-lactones
Synthesis of Saturated Six-Membered Ring Lactones
101