Stereoselective approaches to (E,E,E) and (Z,E,E)-α-chloro-ω-substituted hexatrienes: Synthesis of all E polyenes

Synthesis of 5-(S)-HETE, 5-(S)-HEPE and (+)-zooxanthellactone: Three hydroxylated polyunsaturated fatty acid metabolites

“…The E-selective reduction of internal alkyne in A) vinyl chloride 215 and B) aryl bromide 217. 79,80 Indeed, after we had performed a staggering amount of experimentation, our doubt and apprehension were proved right, as considerable amounts of reductive debromination were observed to occur in all caseseven with careful variation and control of stoichiometry, temperature of -78 °C and also addition of sacrificial bromobenzene.…”

“…In 1982, Sir John Vane was awarded the Nobel Prize in Physiology or Medicine together with Sune K. Bergstrøm and Bengt I. Samuelsson for their efforts concerning prostaglandins and related biologically active molecules. 79 Scheme 1.5 Outline of the biosynthesis of prostaglandins and thromboxanes from AA (1) catalysed by COX-1.…”

“…However, we were wary at the outset given the labile vinyl bromide functionality and the few successful cases of similar transformations are documented in the literature (Scheme 2.18). In the first documented occurrence, a more robust vinyl chloride 215 is present, 79 and in the second example, the alkyne 217 is more electrophilic and reactive due to conjugation with an ester functionality. 80…”

A Protocol for the Direct Conversion of Aldehydes into Arenes - Proof of ­Principle

“…These simple experiments demonstrate the potential of a simple method for extending the synthetic utility of aldehydes. It is potentially applicable to enantiomerically pure aldehydes, to labelled aldehydes ( 11 C, 13 C) and to more highly substituted arenes by simple structural modification of the C 5 entity. Future work will follow these directions.…”

1,2-Dihalogenalkenes: Useful Linchpins to Unsaturated Compounds via Palladium or Nickel Catalysis

“…Carrying out the reaction from chlorotriene derivatives, conjugated polyene compounds containing up to 7 double bonds with all-E configuration can also be prepared. Thus, the coupling reaction between terminal alkynes with achloro-w-arylhexatrienes under Pd-catalysis and subsequent stereoselective reduction of the triple bonds furnished the polyenes with one Z-double bond which are not stable at room temperature and isomerized readily into pure all-E polyenes [81][82][83]87 (Scheme 44).…”