Synthesis of tetradeuterated LTA4 methyl ester

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

“…Some authors replaced quinoline with triethylamine ,, or pyridine (with different ranges of amount = 1/10,000, 1% pyridine). Lellouche et al , observed that the reaction mixture (hexane) must contain exactly 0.01% pyridine in volume. An excess of pyridine (0.02–0.05%) inhibits hydrogen or deuterium absorption.…”

“…Skipped diyne systems were used as precursors for the incorporation of four tritium or deuterium atoms in the synthesis of labeled 5-oxo-ETEs . Application to the preparation of chemically sensitive structures such as leukotriene d 4 -LTA4 was also reported (Scheme ). − Over-reduction and decomposition of the epoxydiene during the purification step dramatically lowered the yield of the semireduction step.…”

Stereocontrolled synthesis of (7E,9Z)‐[9,10‐2H]‐conjugated linoleic acid

“…6 Unfortunately, using this methodology, partial reduction of conjugated enynes often provides conjugated polyalkenes contaminated by over-reduced compounds and/or geometrical isomers. 7,8 Moreover, as reported by Adlof for the preparation of methyl (9Z,11E)- [9, H]-octadecadienoate ((9Z,11E) CLA), 8 the isotopic purity of deuterated conjugated dienes can be lower than the value usually associated with this reaction.…”