Robert Livingston

An Atom-Economic and Selective Ruthenium-Catalyzed Redox Isomerization of Propargylic Alcohols. An Efficient Strategy for the Synthesis of Leukotrienes

Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Bronsted acid isomerize primary and secondary propargylic alcohols in good yields to provide trans enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride, in the presence of indium triflate and camphorsulfonic acid, gives the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity.

Tandem ruthenium-catalyzed redox isomerization--O-conjugate addition: an atom-economic synthesis of cyclic ethers.

An atom-economical method for the convenient synthesis of tetrahydropyrans and tetrahydrofurans is reported. Enones and enals derived from the [IndRu(PPh(3))(2)Cl]-catalyzed redox isomerization of primary and secondary propargyl alcohols undergo a subsequent intramolecular conjugate addition to provide cyclic ethers in excellent yields.