Improved stereoselective reduction of a E,E, conjugated dienyne to a E,E,Z conjugated triene

Are Alkyne Reductions Chemo-, Regio-, and Stereoselective Enough To Provide Pure (Z)-Olefins in Polyfunctionalized Bioactive Molecules?

“…237 The selective reduction of enyne was a key step in the synthesis of dienol sex pheromones 485 and 11cis-retinoids (Scheme 55). 242 Likewise, an excellent chemoselectivity is observed in the presence of an isolated olefin 121,439,488 or terminal diene, 486 a (E,E)-diene, 483,488,490 a (Z,E)-diene, 237,472 a (E,E,E)-triene, 237 or a (E,E,Z)-triene. 237 These selective reaction conditions were widely used in the synthesis of di-or trihydroxylated metabolites of PUFAs such as leukotriene B4 240,488,496 (Scheme 56) or even a 13 C-labeled Scheme 52 249 Scheme 53 493 Scheme 54 495 Scheme 55 analog 489 diHETE, 121 HETE, 439 or resolvin E1 490 (Scheme 57) but also recently resolvins E3, 497 E2, 498 D6, 499 and neuroprotectin D1.…”

Synthesis of 9Z,11E;13-Tetradecatrienal, the Major Component of the Sex Pheromone of the Carob Moth,Ectomyelois ceratoniae(Lepidoptera: Pyralidae).

“…Boland et al 14 ) further improved the reaction by activating the zinc dust with copper and silver salts. These authors and others 15 ) also reported that several other methods (Lindlar catalyst/H 2 , Wilkinson's catalyst/H 2 , diimide) for stereo-and regioselectively reducing the conjugated dienynes were not satisfactory, giving mixtures of products.…”

[6, 7, 10, 11‐13C4]‐Labelled leukotriene B4 synthesis: standard for mass spectrometry determination and metabolic studies

“…This was accomplished by using the couple (PPh 3 ) 4 Pd/CuI (Pd8/ Cu) as a catalyst in the condensation of the terminal acetylenic derivatives % 2 or % 3 with the vinyl halides % 6 or % 9. 15,16 The formation of the C 9 -C 10 and C 7 -C 8 bonds and the details of the synthesis are illustrated in Figure 5. The geometry of the triene system (E, E, Z) was accurately reproduced.…”