Visible-light-mediated copper photocatalysis for organic syntheses

• Yajing Zhang,
• Qian Wang,
• Zongsheng Yan,
• Donglai Ma and
• Yuguang Zheng

Beilstein J. Org. Chem. 2021, 17, 2520–2542, doi:10.3762/bjoc.17.169

• transformation under visible-light irradiation by acting as a catalyst for single-electron reduction and as an intermediate stabilizing agent (Scheme 8). In 2016, the same group [48] reported the [Cu(dap)2]Cl-catalyzed cyclization of α,ω-alkenols and trifluoromethylsulfonyl chloride to form sultones (Scheme 8

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• reaction of alkenols 252 [102]. The proposed mechanism proceeds through a reductive quenching cycle that generates chiral ion pair 253. Subsequent enantioselective cyclisation gives tertiary alkyl radical 254•, which can abstract a hydrogen atom from 2-phenylmalonitrile (255) to afford the desired

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• , exploiting the reactivity of alkene radical cations generated using organic dyes [96][97]. Their seminal work reported the oxidation of the alkenols 22.1 by the Fukuzumi dye (OD2, Scheme 22) [98]. The so-formed radical cation undergoes an intramolecular nucleophilic 5/6/7-exo-trig-cyclization to give the

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• then be involved in another photocatalytic sequence in the presence of α-methylstyrene and water to access β-hydroxysulfones 27 in moderate to good yields (Scheme 22) [29]. Interestingly, this process can be realised in one-pot. Reiser and co-workers also envisioned that using alkenols as substrates in

• alkenols bearing substituents on the double bond or close to it favoured the formation of the chlorotrifluoromethylated products. The mechanism of the reaction was supposedly identical to the one proposed for the trifluoromethylchlorosulfonylation of simple alkenes, although obviously including an

• trifluoromethylchlorosulfonylation/cyclisation reaction of alkenols: a route to trifluoromethylated sultones. First direct C–H trifluoromethylation of arenes and proposed mechanism. Direct C–H trifluoromethylation of five- and six-membered (hetero)arenes under photoredox catalysis. Alternative pathway for the C–H

Identification, synthesis and mass spectrometry of a macrolide from the African reed frog Hyperolius cinnamomeoventris

• Markus Menke,
• Pardha Saradhi Peram,
• Iris Starnberger,
• Walter Hödl,
• Gregory F.M. Jongsma,
• David C. Blackburn,
• Mark-Oliver Rödel,
• Miguel Vences and
• Stefan Schulz

Beilstein J. Org. Chem. 2016, 12, 2731–2738, doi:10.3762/bjoc.12.269

• reed frog, Hyperolius cinnamomeoventris. The location and configuration of the double bond might be relevant for their function, as it is the case in many insect pheromones. In typical pheromone components of insects, including long chain alkenes, alkenols, or unsaturated aldehydes, the location of the

Visible-light-induced bromoetherification of alkenols for the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans

• Run Lin,
• Hongnan Sun,
• Chao Yang,
• Youdong Yang,
• Xinxin Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2015, 11, 31–36, doi:10.3762/bjoc.11.5

• photoredox-catalyzed bromoetherification of alkenols is described. This approach, with CBr4 as the bromine source through generation of bromine in situ, provides a mild and operationally simple access to the synthesis of β-bromotetrahydrofurans and -tetrahydropyrans with high efficiency and regioselectivity

• . Keywords: alkenols; bromoetherification; photoredox catalysis; visible light; Introduction The halocyclization of alkenes provides an excellent synthetic method for halogenated heterocycles [1][2][3]. In recent years, haloaminocyclization [4][5], halolactonization [6][7] and haloetherification [8][9] of

• -bromosuccinimide (NBS) is an effective alternative for the bromocyclization [11][12][13][14]. Furthermore, Wei Sun and co-workers disclosed an intriguing strategy to access the haloetherfication of alkenols with N-chlorosuccinimide (NCS), leading to the synthesis of β-chlorotetrahydrofurans [15]. Recently we have

Palladium-catalysed cyclisation of alkenols: Synthesis of oxaheterocycles as core intermediates of natural compounds

• Miroslav Palík,
• Jozef Kožíšek,
• Peter Koóš and
• Tibor Gracza

Beilstein J. Org. Chem. 2014, 10, 2077–2086, doi:10.3762/bjoc.10.216

• ., Koreničova 1, SK-811 03 Bratislava, Slovakia 10.3762/bjoc.10.216 Abstract The study of Pd-catalysed cyclisation reactions of alkenols using different catalytic systems is reported. These transformations affect the stereoselective construction of mono- and/or bicyclic oxaheterocyclic derivatives depending on

• a starting alkenol. The substrate scope and proposed mechanism of Pd-catalysed cyclisation reactions are also discussed. Moreover, the diastereoselective Pd-catalysed cyclisation of appropriate alkenols to tetrahydrofurans and subsequent cyclisation provided properly substituted 2,5-dioxabicyclo

• [2.2.1]heptane and 2,6-dioxabicyclo[3.2.1]octane, respectively. Such bicyclic ring subunits are found in many natural products including ocellenynes and aurovertines. Keywords: alkenols; cycloetherification; homogeneous catalysis; natural products; palladium; Introduction Oxaheterocycles of various

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

• Vadim A. Soloshonok and
• Donna J. Nelson

Beilstein J. Org. Chem. 2011, 7, 744–758, doi:10.3762/bjoc.7.85

• addition reactions of chiral ArSeOTf to alkenes Stereoselectivity Some experimental and computational [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][89] data suggest that, in the reactions of alkenols such as 4 (Scheme 2) with the chiral selenium electrophile, the stereochemistry of

• ][34][35][36][37][38][39][40][41][42][43][60][61][62][63][64][66][69][70][71]. Scheme 2 shows the reactions of 1 and 2 with alkenols 4, and the stereochemical outcome of each is compiled in Table 4. It should be noted that the absolute configuration of products from reactions of 1 and of 2 with

• alkenols 4 is reversed, because of the opposite stereochemistry of the chiral stereogenic centers in 1 versus 2. While not included in this study, it should be emphasized that analogous stereochemical outcomes were observed in the corresponding reactions of chiral electrophiles 1 and 2 with carboxylic

Oxidative cyclization of alkenols with Oxone using a miniflow reactor

• Yoichi M. A. Yamada,
• Kaoru Torii and
• Yasuhiro Uozumi

Beilstein J. Org. Chem. 2009, 5, No. 18, doi:10.3762/bjoc.5.18

• Yoichi M. A. Yamada Kaoru Torii Yasuhiro Uozumi RIKEN, Hirosawa, Wako, Saitama 351-0198, Japan Institute for Molecular Science (IMS), Myodaiji, Okazaki, Aichi 444-8787, Japan 10.3762/bjoc.5.18 Abstract A miniflow system for oxidative cyclization of alkenols with Oxone was developed. Thus, the

• oxidative cyclization of (Z)- and (E)-alkenols in i-PrOH with an aqueous solution of Oxone proceeded smoothly and safely in a PTFE tube without any exogenous catalytic species, and was subsequently quenched in a flow-reaction manner to afford the corresponding furanyl and pyranyl carbinols quantitatively

• within 5 or 10 min of residence time. Keywords: alkenols; cyclic ethers; miniflow reaction; oxidative cyclization; Oxone; Introduction The development of flow-reaction systems for molecular transformations is an important goal in organic syntheses. Recently, innovative devices such as micro- and