An alkyne hydration of terminal and internal alkynes is reported using a zwitterionic N‐heterocyclic carbene gold catalyst [(BNHC)Au(SMe2)] in the absence of silver and Brønsted acid additives. The hydration demonstrates good regioselectivity in alkyne hydration and chemoselectivity for internal alkynes vs. terminal. In addition, (BNHC)Au(SMe2) performs a propargyl alcohol hydration to predominantly form α‐hydroxymethyl ketone over the more common Meyer–Schuster rearrangement product. While complex (BNHC)Au(SMe2) is active without silver additives, addition of silver hexafluoroantimonate (AgSbF6) increases reaction rate and decreases selectivity for internal alkyne hydration over terminal substrates. To the best of our knowledge, the rate enhancement of (BNHC)Au(SMe2) by AgSbF6 is the first such demonstration of a silver effect for a “halide‐free” Au catalyst.magnified image

The Cu(II) complex 1, Cu(II)-6-N-3,5-di-tert-butylsalicylidene-6,7-quinoxalinol-diamine, has been developed to address problems with current methods of catalytic oxidation using tert-butyl hydroperoxide (TBHP). Complex 1 demonstrated an increased capability to utilize TBHP while limiting interference from free radical reactions and was demonstrated to be highly effective in the oxidations of a variety of olefins.

The copper(II) complex of 2-quinoxalinol salen (salqu) is an efficient catalyst for the selective oxidation of propargylic alcohols to yield the corresponding α,β-acetylenic carbonyl compounds when used in combination with the oxidant tertbutyl hydroperoxide (TBHP). Excellent yields (up to 99 %) are achieved for a variety of propargylic alcohols within 1 h of reaction time. The (salqu)copper(II) complex with TBHP[a]

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A series of complexes Pd(IPr)(C(O)C 9 H 6 N)X has been prepared where X is a weakly coordinating anion (WCA). [Pd(IPr)(C(O)C 9 H 6 N)] + can be isolated as a 3coordinate, air-and moisture-stable Pd(II) cation when paired with sterically encumbered WCAs. Using NMR, IR, X-ray diffraction, and computational (DFT, NBO) techniques, the coordination ability of WCAs in both solid and solution state is compared. The IPr methine isopropyl 1 H NMR chemical shift and the anion's percent buried volume (%V bur ) are highly sensitive to the steric encumbrance of the anion, while IR and NBO analysis offer a measure of relative donor strength. On the basis of computed ν CO , the coordinating abilities of anions studied are as follows BAr F 4 − ∼ [(BCF) 2 (imid)] −

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The copper(II) complex of 2‐quinoxalinol salen (salqu) is an efficient catalyst for the selective oxidation of propargylic alcohols to yield the corresponding α,β‐acetylenic carbonyl compounds when used in combination with the oxidant tert‐butyl hydroperoxide (TBHP). Excellent yields (up to 99 %) are achieved for a variety of propargylic alcohols within 1 h of reaction time. The (salqu)copper(II) complex with TBHP can be used with propargylic alcohols that contain alkyl groups in the α‐position, which can be difficult to oxidize selectively with other commonly available methods. By using this catalytic protocol, excellent selectivity was also achieved for the oxidation of propargylic alcohols over that of isolated hydroxy groups, triple bonds, or propargylic methylene groups.