Efficient Dehydration of C_6–10-α,ω-Alkanediols to Alkadienes as Catalyzed by Aliphatic Acids

Abstract

The aliphatic-acid-mediated dehydration of C6–10-α,ω-alkanediols to alkadienes proceeds in a stepwise manner: C6–10-α,ω-alkanediols react with aliphatic acids first to generate diesters; subsequent pyrolysis of the latter produces alkadienes. The highest yields of 1,5-hexadiene, 1,7-octadiene, and 1,9-decadiene were up to 70.3, 74.8, and 90.3%, respectively. It turned out that pyrolysis favors the diester with a longer carbon chain more, while acetic acid outperformed the other aliphatic acids in the pyrolysis step that a relatively lower temperature was enough for a high yield of alkadienes.

Ru–Mg promoted reductive cross-coupling of allyl bromides and alkenes to synthesize 1,7-octadienes with an all-carbon quaternary center

“…1 Therefore, many efforts have been devoted to developing approaches for preparing 1,7-octadienes; however, there only exist quite a few methods such as the catalytic decarboxylation of alkanedioic acid, dehydration of alkanediol, metathesis of cyclohexene with ethylene, Grignard reaction of halogenated hydrocarbons, or reductive coupling reaction of halogenated alkenes (Scheme 1A). 2 Apparently, all these synthetic methods are currently the most reliable methods to access simple terminal 1,7-octadienes due to the low cost of raw materials, convenient post-treatment and less pollution, but for the synthesis of complex terminal 1,7-octadienes containing an all-carbon quaternary center there are great challenges. Given the importance of terminal 1,7-octadienes in materials science, the exploration of an alternative general and practical protocol for constructing complex terminal 1,7-octadienes with an all-carbon quaternary center from simple and readily available raw materials is highly desirable.…”