Alkynes, with alcohols Sonogashira

Activated and deactivated positions in halopyridines exhibit marked difference in reactivity in palladium chemistry, whereas little difference in reactivity was observed among 2-, 4-, and 5-positions of halopyrimidines for their Sonogashira reactions [84]. While 2-iodo-4,6-dimethylpyrimidine was the most suitable substrate for preparing internal alkyne 176, the reaction of either the corresponding bromide or chloride was less efficient [85]. Good to excellent yields were obtained for the preparation of alkynylpyrimidines from most terminal alkynes with the exception of propargyl alcohols. Later reports showed that... 

A synthesis of the biaryl moiety and the seven-membered ring core 3.16 of allocolchicine employed a C-H activation reaction as part of the intramolecular biaryl formation (Scheme 3.19). The starting material was prepared by the acid chloride variant of the Sonogashira reaction (Section 2.8), coupling alkyne 3.17 with acid chloride 3.18. Asymmetric reduction of the ketone 3.19, protection of the alcohol and reduction of the alkyne gave the substrate 3.20 for CH activation. Diimide, generated in situ, was employed for the alkyne reduction to avoid potential problems of over reduction. C-H activation and biaryl formation was then... 

More recent applications of the Sonogashira reaction in PUFA synthesis include Spurs and Rodriguez s synthesis of maresin 1 (56) [72], a potent anti-inflammatory lipid mediator derived from DHA (7). As shown in Scheme 3.21, the Sonogashira cross coupling reaction of alkyne 82, bearing an unprotected secondary alcohol, with vinyl iodide 83, provided compound 84. Then, removal of the TES group, Boland reduction of the triple bond, and subsequent hydrolysis of the methyl ester afforded maresin 1 (56). 

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