Synthesis of bis(3-{[2-(allyloxy)ethoxy]methyl}-2,4,6-trimethylbenzoyl)(phenyl)phosphine oxide – a tailor-made photoinitiator for dental adhesives

• Norbert Moszner,
• Iris Lamparth,
• Jörg Angermann,
• Urs Karl Fischer,
• Frank Zeuner,
• Thorsten Bock,
• Robert Liska and
• Volker Rheinberger

Beilstein J. Org. Chem. 2010, 6, No. 26, doi:10.3762/bjoc.6.26

• characterization of WBAPO The synthesis of bisacylphosphines and their oxides often start either from P,P-dichlorophenylphosphine (PhPCl2) [13] or free phenylphosphine [14]. We chose to use the PhPCl2-route since primary phosphines have an unpleasant smell, a high toxicity and are very air-sensitive. Furthermore

From discovery to production: Scale- out of continuous flow meso reactors

• Peter Styring and
• Ana I. R. Parracho

Beilstein J. Org. Chem. 2009, 5, No. 29, doi:10.3762/bjoc.5.29

• activating agents such as substituted phosphines, or else catalysts possessing ligands with complex and expensive motifs [1]. Often, the scale at which such reactions are performed is far greater than that required for initial characterisation and property screening [2][3]. Once a compound is identified for

• reaction. This makes catalyst recovery and re-cycling problematic if not impossible. It also leads to the possibility of metal contamination at trace levels in the final product. Furthermore, added phosphines and other activating agents tend to be expensive and also difficult to recover, adding both an

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• observed to be higher in the microreactor. A single-channel, falling film microreactor designed specifically for efficient gas-liquid phase contact was used to screen the asymmetric hydrogenation of (Z)-methyl acetamidocinnamate 4 and related substrates (Scheme 2) [13][14]. Seventeen chiral phosphines were

Efficient 1,4-addition of α-substituted fluoro(phenylsulfonyl)methane derivatives to α,β-unsaturated compounds

• G. K. Surya Prakash,
• Xiaoming Zhao,
• Sujith Chacko,
• Fang Wang,
• Habiba Vaghoo and
• George A. Olah

Beilstein J. Org. Chem. 2008, 4, No. 17, doi:10.3762/bjoc.4.17

• nucleophile to a variety of α,β-unsaturated compounds has been achieved under mild conditions using either phosphines or potassium carbonate at room temperature. α-Substituted fluoro(phenylsulfonyl)methane easily undergoes Michael addition to α,β-unsaturated ketones, esters, nitriles, sulfones, as well as

• -stabilizing abilities of the two strong electron-withdrawing groups are not sufficient to overcome the well-known carbanion destabilization by the adjacent fluorine [25]. With this in mind, we first opted to use phosphines as nucleophilic catalysts. Concerning applications of 3a–d, and 3f in constructing the

• in the course of above-mentioned Michael reactions, under the reaction conditions. We then screened various electronically and sterically different phosphines such as PPh3, Bu3P, (iPr)3P and PMe3. Initial experiments revealed that the catalytic activity of phosphines and phosphine loading (varying

Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation

• Ivana Kosiova,
• Andrea Janicova and
• Pavol Kois

Beilstein J. Org. Chem. 2006, 2, No. 23, doi:10.1186/1860-5397-2-23

• Ivana Kosiova Andrea Janicova Pavol Kois Comenius University, Faculty of Natural Sciences, Department of Organic Chemistry, Mlynska dolina, Pavilon CH2, SK-84215 Bratislava, Slovak Republic 10.1186/1860-5397-2-23 Abstract Background Reaction of azides with triaryl phosphines under mild conditions

• , boranes) and at N3 with nucleophiles, very frequently with phosphorous nucleophiles. Reaction of azides with triaryl phosphines under mild conditions gives iminophosphoranes without formation of any byproducts. [14] The intermediate which is formed almost quantitatively can be rapidly hydrolysed to the

Mixtures of monodentate P-ligands as a means to control the diastereoselectivity in Rh-catalyzed hydrogenation of chiral alkenes

• Manfred T. Reetz and
• Hongchao Guo

Beilstein J. Org. Chem. 2005, 1, No. 3, doi:10.1186/1860-5397-1-3

• extensive manner. For example, Brown reported the Rh-catalyzed hydrogenation of the racemic allylic alcohol 1 with formation of diastereomers 2 and 3, ketone 4 forming as a side product due to undesired isomerization.[29] From a small collection of mono-phosphines and bidentate diphosphines, diphos-4 led to