Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• -monosubstituted dipyrrin 3a, was obtained via a one-pot reaction in 18% yield (in three steps from 2). On the other hand, the β,β'-diethynyl-substituted BODIPY derivatives 5a and 6a, were synthesized by a similar gold-catalyzed reaction of unsubstituted BODIPY 1a in 38% and 2% yields, respectively, in the

Synthesis of 1,2-divinylcyclopropanes by metal-catalyzed cyclopropanation of 1,3-dienes with cyclopropenes as vinyl carbene precursors

• Jesús González,
• Alba de la Fuente,
• María J. González,
• Laura Díez de Tejada,
• Luis A. López and
• Rubén Vicente

Beilstein J. Org. Chem. 2019, 15, 285–290, doi:10.3762/bjoc.15.25

• example of isolation of these structures. Indeed, Lee and co-worker found that the corresponding gold-catalyzed reaction leads to ring-opened products through a facile oxy-Cope-rearrangement [28]. Moreover, these structures are also not accessible with metal–vinyl carbenes generated from vinyldiazo

Synthesis of indolo[1,2-c]quinazolines from 2-alkynylaniline derivatives through Pd-catalyzed indole formation/cyclization with N,N-dimethylformamide dimethyl acetal

• Antonio Arcadi,
• Sandro Cacchi,
• Giancarlo Fabrizi,
• Francesca Ghirga,
• Antonella Goggiamani,
• Antonia Iazzetti and
• Fabio Marinelli

Beilstein J. Org. Chem. 2018, 14, 2411–2417, doi:10.3762/bjoc.14.218

• -catalyzed reaction of 15a with aldehydes as electrophiles resulted in the divergent formation of 11H-indolo[3,2-c]quinolines 17 (Scheme 5b) [32] through functionalization of C-3 position of the indole ring instead of N-1. The sequential reaction shown in Scheme 5, path a, probably occurs through cyclization

• palladium-catalyzed reaction of 15a in the presence of DMFDMA led directly to the formation of quinazoline 13a in 71% yield through a sequential process (Scheme 5a). The selective formation of products 13 from 15 (and also from 3-unsubstituted indoles 14) is not trivial, since the previously reported gold

Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products

• Sultan Taskaya,
• Nurettin Menges and
• Metin Balci

Beilstein J. Org. Chem. 2015, 11, 897–905, doi:10.3762/bjoc.11.101

• hemiacetals after cascade reactions. Keywords: alkyne cyclization; gold-catalyzed reaction; indolo-oxazin-1-one; marine natural products; pyrrolo-oxazin-1-one; Introduction Pyrrole-containing heterocycles are widely distributed within a large number of natural products and biologically active molecules [1

Gold(I)-catalyzed 6-endo hydroxycyclization of 7-substituted-1,6-enynes

• Ana M. Sanjuán,
• Alberto Martínez,
• Patricia García-García,
• Manuel A. Fernández-Rodríguez and
• Roberto Sanz

Beilstein J. Org. Chem. 2013, 9, 2242–2249, doi:10.3762/bjoc.9.263

• -catalyzed reaction of 7-phenyl-1,6-enynes with a terminal double bond gives rise to bicyclo[3.2.0]heptene derivatives [19][21]. Despite the numerous studies about the metal-catalyzed transformations of 1,6-enynes, o-(alkynyl)-(3-methylbut-2-enyl)benzenes 1 that are also 1,6-enynes bearing an attached aryl

• to cyclopenta[b]naphthalenes VIII or, alternatively, a 6-endo cyclization to bicyclo[4.1.0]hept-4-enes like IX [18][19] (Scheme 1). In the case that MeOH is present a 5-exo methoxycyclization is observed, e.g., in the formation of X resembling the behaviour of I [16][20]. In addition, the gold

Gold-catalyzed reaction of oxabicyclic alkenes with electron-deficient terminal alkynes to produce acrylate derivatives

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 1969–1976, doi:10.3762/bjoc.9.233

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

• bridging C–C bond and a formal [1,2]-alkynyl shift. Li et al. reported the first gold-catalyzed reaction of propargylcyclopropene systems 212 which affords benzene derivatives 213 in high yields [94] (Scheme 39). Only few efficient methods have emerged for the synthesis of cyclobutane derivatives, which

When gold can do what iodine cannot do: A critical comparison

• Sara Hummel and
• Stefan F. Kirsch

Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97

• the NIS-mediated pathway towards iodofuranones, the presence of a proton source is of no importance since both silyloxy and hydroxy substituents are reactive under the conditions. Another example where the iodine-induced reaction nicely parallels the gold-catalyzed reaction pathway was reported by

• . However, Larock and co-workers also investigated a cyclization process where the proton on the heteroatom is absent (e.g., 13→14) [75]. After activation by the electrophile, the iodine substituent remains in the indole framework (Scheme 5b) since the 1,3-migration step observed in the gold-catalyzed

• reaction does not occur via electrophilic activation. Instead, due to the iodide ion still present in the reaction mixture, the ammonium ion intermediate undergoes SN1 or SN2 substitution, or even E2 elimination of an alkyl group. This system yields products in up to quantitative yields, and successfully

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

• activators [31]. Since AgOTf and BF3·OEt2 led to the same naphthalene product 21, the authors suspected that traces of the Brønsted acid (HOTf) present in the silver salt may be the actual catalyst and may also modify the regioselectivity observed in the gold-catalyzed reaction. Thus, several basic additives

• cyclopropene-ynes involving a double cleavage process. Gold-catalyzed reaction of cyclopropene-ynes, cyclopropene-enes and cyclopropene-allenes.

Gold-catalyzed naphthalene functionalization

• Pedro J. Pérez,
• M. Mar Díaz-Requejo and
• Iván Rivilla

Beilstein J. Org. Chem. 2011, 7, 653–657, doi:10.3762/bjoc.7.77

• . The Buchner reaction applied to naphthalene. (a) Teyssié's system. (b) Müller's system. The gold-catalyzed reaction of benzene and EDA. The functionalization of naphthalene with ethyl diazoacetate catalyzed by the complexes (a) 1a and (b) 1b. The functionalization of naphthalene with ethyl 2

Gold-catalyzed alkylation of silyl enol ethers with ortho-alkynylbenzoic acid esters

• Haruo Aikawa,
• Tetsuro Kaneko,
• Naoki Asao and
• Yoshinori Yamamoto

Beilstein J. Org. Chem. 2011, 7, 648–652, doi:10.3762/bjoc.7.76

• , the Lewis acid-catalyzed reaction of silyl enol ethers with alkyl halides is well known as one of the most efficient preparative methods for regio-defined α-alkylated ketones (path a in Scheme 1) [5][6][7][8][9][10][11][12][13][14][15][16][17]. In contrast, in this paper, we report a gold-catalyzed

• reaction of silyl enol ethers with ortho-alkynylbenzoic acid esters which leads to the formation of α-alkylated silyl enol ethers (path b). We examined the reactions of silyl enol ether 1a with ortho-alkynylbenzoic acid benzyl esters 2 in the presence of gold catalysts under several reaction conditions and

Sequential Au(I)-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates

• Lei Zhou,
• Yizhou Liu,
• Yan Zhang and
• Jianbo Wang

Beilstein J. Org. Chem. 2011, 7, 631–637, doi:10.3762/bjoc.7.74

• –alkyne cyclization. Since gold complexes are well-known for their efficacy in activating alkynes, we reasoned that a concurrent catalysis based on gold-catalyzed reaction of diazo compounds and alkynes might be possible [30]. Herein we report such a catalytic system, namely a gold(I)-catalyzed insertion

• ][40][41][42][43][44][45][46][47][48][49][50][51]. Moreover, this study further demonstrates the possibility to incorporate gold-catalyzed reaction of diazo compounds with various other gold-catalyzed transformations. Further studies to broaden the scope of these reactions are currently underway

Gold-catalyzed heterocyclizations in alkynyl- and allenyl-β-lactams

• Benito Alcaide and
• Pedro Almendros

Beilstein J. Org. Chem. 2011, 7, 622–630, doi:10.3762/bjoc.7.73

• (Scheme 14). Interestingly, the gold-catalyzed reaction of 28, with a (methoxymethyl)oxy moiety instead of the free hydroxy group, also proceeded smoothly to give the cyclization product 27b, albeit in lower yield (Scheme 14). Notably, the observed regioselectivity (5-exo cyclization) was unaffected by

A gold-catalyzed alkyne-diol cycloisomerization for the synthesis of oxygenated 5,5-spiroketals

• Sami F. Tlais and
• Gregory B. Dudley

Beilstein J. Org. Chem. 2011, 7, 570–577, doi:10.3762/bjoc.7.66

• methanol, as pre-mixing the gold(I) chloride with methanol and aging this mixture prior to adding the substrate results in a less efficient reaction. This is not the first time that we have observed the importance of the order of addition in a gold-catalyzed reaction in a protic solvent [38], but