Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• bromopropargylic alcohols and Cs2CO3. Keywords: acetylenic alcohol; bromoacetylene; 1,3-dioxolan-2-one; phenols; phenoxyketone; Introduction Due to the relative stability, ease of handling and the presence of reactive sites, bromoacetylenes are widely applied in synthetic organic chemistry. They are known to be

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• the alkyne may be influenced by diastereomers; in the case of cis-isomer 82 exocyclic enol ether 83 was formed while for trans-isomer 84 the reaction takes place with a much slower rate yielding endocyclic enol ether 85 as the only product (Scheme 27) [79]. trans-Acetylenic alcohol 86 on treatment

• . Synthesis of exocyclic and endocyclic enol ether derivatives. Cyclization of trans-acetylenic alcohol by treatment with HgCl2. Synthesis of benzofuran derivatives in presence of HgCl2. a) Hg(II)-salt-mediated cyclization of 4-hydroxy-2-alkyn-1-ones to furan derivatives and b) its mechanistic pathway

Total synthesis of panicein A₂

• Lili Yeung,
• Lisa I. Pilkington,
• Melissa M. Cadelis,
• Brent R. Copp and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 1991–1996, doi:10.3762/bjoc.11.215

• proposed that panicein A2 (5) could be synthesised from the cyclisation and subsequent deprotection of propargyl ether 8. Ether 8 could be formed through the addition of the appropriate phenol to acetylenic alcohol 9, which itself can be derived from aldehyde 10 (Figure 3). Results and Discussion Synthesis

2-(1-Hydroxypropyn-2-yl)-1-vinylpyrroles: the first successful Favorsky ethynylation of pyrrolecarbaldehydes

• A. V. Ivanov,
• V. S. Shcherbakova,
• I. A. Ushakov,
• L. N. Sobenina,
• O. V. Petrova,
• A. I. Mikhaleva and
• B. A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 228–232, doi:10.3762/bjoc.11.25

• give inferior yields of the corresponding acetylenic alcohol. In the above optimal superbase composition, ethanol was proved to be a necessary component as it homogenizes the reaction mixture and provides for the controlled decrease of the basicity [23][24]. The latter is needed to prevent the

• reliable conclusion, although the higher yield of acetylenic alcohol 2d (94%) corresponds to the expectation of the enhanced electron-withdrawing effect of the 3-metoxyphenyl group compared to the unsubstituted phenyl (1c → 2c) that should increase the electrophilicity of the carbonyl function. The range

• has been developed. As an example of a promising application of the synthesized compounds as building blocks we have demonstrated the condensation of acetylenic alcohol 2c with 2-phenylpyrrole to afford the corresponding dipyrrolomethane 3 in 64% yield (Scheme 2). The reaction readily proceeds at room

The use of silicon- based tethers for the Pauson- Khand reaction

• Adrian P. Dobbs,
• Ian J. Miller and
• Saša Martinović

Beilstein J. Org. Chem. 2007, 3, No. 21, doi:10.1186/1860-5397-3-21

• procedure was developed, initially adding the allyl arm via the allyl Grignard reagent, followed by a more standard silyl ether formation using an acetylenic alcohol and imidazole (without isolating the intermediate silyl chloride). (Isolation of the intermediate diisopropylallylsilyl chloride was