The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• gold ketocarbenes 104 from alkynes (Scheme 22) [95]. Those carbenes are then capable of further transformations, including C–H bond insertion and the reaction with other alkynes. Notably, this approach avoids the use of unstable diazo compounds. The Zhang group also demonstrated that the gold carbenes

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• could be formally categorized as a [2 + 1] cycloaddition. In particular, they showed that it is possible to trap the intermediate gold–carbenes resulting from a 1,2-acyloxy migration in propargyl esters such as 1, with external alkenes (e.g. vinylarenes), to give cyclopropane products [41]. The racemic

• -workers reported another example of a highly enantioselective gold-catalyzed cyclopropanation reaction by using diazo compounds as a source of gold carbenes. In particular, the authors demonstrated that the chiral bisgold complex Au6, derived from the spiroketal bisphosphine ligand, was a very efficient

Gold-catalyzed regioselective oxidation of propargylic carboxylates: a reliable access to α-carboxy-α,β-unsaturated ketones/aldehydes

• Kegong Ji,
• Jonathan Nelson and
• Liming Zhang

Beilstein J. Org. Chem. 2013, 9, 1925–1930, doi:10.3762/bjoc.9.227

• carboxylate; Introduction We reported in 2010 [1] that α-oxo gold carbenes could be conveniently generated as reactive intermediates in gold-catalyzed intermolecular oxidation of alkynes. By using pyridine N-oxides [1] and later 8-substituted quinoline N-oxides [2] as the external oxidants, this approach

• permits a safe and efficient access to α-oxo gold carbenes without resorting to the dediazotization strategy [3][4][5] using hazardous and potentially explosive diazo substrates (Scheme 1). Since then an array of versatile synthetic methods has been developed based on the general approach by us [2][6][7

• migration might be an even less meaningful event in the reaction; b) it is known that the gold carbenes of type B can be readily oxidized by Ph2S=O [33], which, however, is an inefficient oxidant for generating α-oxo gold carbenes of type A via alkyne oxidation [34][35]; when the N-oxide 3 is replaced by

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• gold-catalyzed synthesis of dihydrofuran-3-ones 63, in which terminal alkynes 62 were used as equivalents of α-diazo ketones to generate α-oxo gold carbenes (Scheme 12) [37]. The α-oxo gold carbenes were produced via gold-catalyzed intermolecular oxidation of 62. This provides improved synthetic

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• 88 upon cyclopropyl ring expansion. Nevado and co-workers [59] have also recently used cyclopropyl intermediates, generated in situ via alkene cyclopropanations mediated by gold carbenes, for the stereocontrolled synthesis of 5- and 7-membered-rings (Scheme 27). This method was subsequently applied

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• in a variety of gold-catalyzed reactions. The different contributions in this growing research area are summarized in this review. Keywords: cyclopropenes; gold carbenes; gold catalysis; gold-stabilized allylic cations; ring-opening; Review Introduction Homogeneous gold catalysis has become a

• gold-carbon order in the so-called organogold carbenoids. In the broad repertoire of gold-catalyzed organic transformations, gold-stabilized carbocations or, more often gold carbenes, can be found as intermediates in proposed mechanistic pathways, but the true nature of the organogold species had been

• a matter of debate [27]. Structural considerations: Gold-stabilized carbocations or gold carbenes? In 2008, Fürstner et al. took advantage of the ring-opening of 3,3-disubstituted cyclopropenes to generate organogold species and characterize them by NMR spectroscopy [16]. Whereas, 3,3

Gold-catalyzed regioselective oxidation of terminal allenes: formation of α-methanesulfonyloxy methyl ketones

• Yingdong Luo,
• Guozhu Zhang,
• Erik S. Hwang,
• Thomas A. Wilcoxon and
• Liming Zhang

Beilstein J. Org. Chem. 2011, 7, 596–600, doi:10.3762/bjoc.7.69

• ][13][14][15][16][17] or via allenes generated in situ [18][19][20][21]. We have recently shown that highly reactive gold carbenes can be generated from alkynes via gold-promoted intermolecular oxidation by pyridine/quinoline N-oxides [22][23][24][25], making benign alkynes effective surrogates of