Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• of this kind of reaction is the catalytic use of the hydride donor, in this case phenylsilane (PhSiH3), due to the regeneration of the active metal hydride species in the cycloisomerization mechanism pathway (Scheme 18). The lower cyclization constant for the six-membered ring formation, in

• elimination step, a branched cross-coupling product was observed, and the Ni(I) species formed was reduced to generate the catalytically active Ni(0) species (F). The same authors then employed a catalytic system composed of Mn(III)tris(dipivaloylmethane) and phenylsilane in the MHAT cycle and Ni(II)bis

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• phenylsilane (2d), the phenoxasilin product 3d was formed in 59% yield using conditions B and in 63% yield under conditions A. Di(4-bromophenyl)dihydrosilane (2e) was transformed successfully into phenoxasilin 3e in 83% yield without loss of the bromine substituent. The reaction system was also applicable for

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• amount of reductant, as exemplified by the reductive aldol reaction of α,β-unsaturated nitriles catalyzed by cobalt using phenylsilane as the reductant [34]. Yamada found that the reductive carboxylation of α,β-unsaturated compounds with CO2 proceeded in the presence of Co catalysts and reductants

Novel unit B cryptophycin analogues as payloads for targeted therapy

• Eduard Figueras,
• Adina Borbély,
• Mohamed Ismail,
• Marcel Frese and
• Norbert Sewald

Beilstein J. Org. Chem. 2018, 14, 1281–1286, doi:10.3762/bjoc.14.109

• column chromatography. The allyl ether in 23 was cleaved using Pd(PPh3)4 as Pd(0) source and phenylsilane as scavenger to obtain the cryptophycin analogue 24 in good purity. Biological evaluation The biological activity of the modified unit B analogues was determined in a cell viability assay using the

• ) K2CO3, DME/ethylene glycol (2:1 v/v), rt, 5 min; (e) Pd(PPh3)4, phenylsilane, CH2Cl2, rt, 7 h. Cytotoxicity of cryptophycin-52 and its unit B analogues. Binding energies for the different cryptophycin analogues. Supporting Information Supporting Information File 340: Experimental part and analytical

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• Wanda H. Midura Aneta Rzewnicka Jerzy A. Krysiak Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Department of Heteroorganic Chemistry, Sienkiewicza 112, 90-363 Łódź, Poland 10.3762/bjoc.13.150 Abstract The reduction using phenylsilane in a KOH-catalyzed system was

• group reduction. Investigations performed on different α-sulfinylcarbonyl compounds revealed that phenylsilane treatment constitutes a regiospecific method for the desulfinylation of a-sulfinylesters; for corresponding ketones the reaction course depends on the character of the carbonyl group. Keywords

• : desulfinylation; phenylsilane; reduction; regioselectivity; α-sulfinylesters; Introduction The conversion of carboxylic acid derivatives to the corresponding alcohols is one of the fundamental processes in organic synthesis. Over the past decades, many reagents and conditions for this transformation have been

Catalytic Wittig and aza-Wittig reactions

• Zhiqi Lao and
• Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

• reactions [19], and that the addition of 4-nitrobenzoic acid facilitated the phosphine oxide reduction step using phenylsilane (PhSiH3) instead of diphenylsilane [20]. Using this combination of 4-nitrobenzoic acid and phenylsilane for phosphine oxide reduction allowed reactions starting with phosphine oxide

• reactions butylene oxide was used as a base precursor, phenylsilane was the reducing reagent, and the reactions were performed using microwave irradiation (MWI). Subsequently, Werner et al. reported the scope and limitations of such microwave-assisted catalytic Wittig reactions using tributylphosphine

• , phenylsilane and butylene oxide [23][24], and reactions with the combination of achiral 30, trimethoxysilane ((MeO)3SiH) and sodium carbonate using conventional heating [25]. Additionally, the same authors have reported base-free Wittig reactions using diethyl maleate (31) as the starting material to form

A concise enantioselective synthesis of the guaiane sesquiterpene (−)-oxyphyllol

• Martin Zahel and
• Peter Metz

Beilstein J. Org. Chem. 2013, 9, 2028–2032, doi:10.3762/bjoc.9.239

• for 1 h, and phenylsilane (196.5 mg, 1.816 mmol) was added afterwards. After a reaction time of 22 h, ethyl acetate was added, and the mixture was filtered through silica gel. The filtrate was concentrated under reduced pressure, and the residue was purified by flash chromatography (isohexane/ethyl

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• highly atypical but may be due to the templating effect of Na+. Separation by column chromatography afforded the cone conformer in 72% yield although the partial-cone was never obtained in a pure form. Reduction by phenylsilane (PhSiH3) gave the corresponding cone and partial-cone phosphines 26