Reversible intramolecular photocycloaddition of a bis(9-anthrylbutadienyl)paracyclophane – an inverse photochromic system. (Photoactive cyclophanes 5)

• Henning Hopf,
• Christian Beck,
• Jean-Pierre Desvergne,
• Henri Bouas-Laurent,
• Peter G. Jones and
• Ludger Ernst

Beilstein J. Org. Chem. 2009, 5, No. 20, doi:10.3762/bjoc.5.20

• , was irradiated at λ > 400 nm for 2 h with a high pressure mercury lamp in a Pyrex photoreactor. The cooling tube of the latter was filled with a NaNO2 solution (75 g/L) maintaining the reaction medium at 10–20 °C. After the end of irradiation, the solution was concentrated at ca 15 °C to 10 mL; then

Chemoselective reduction of aldehydes by ruthenium trichloride and resin- bound formates

• Basudeb Basu,
• Bablee Mandal,
• Sajal Das,
• Pralay Das and
• Ashis K. Nanda

Beilstein J. Org. Chem. 2008, 4, No. 53, doi:10.3762/bjoc.4.53

• alternative to hydrogenation using molecular hydrogen [1][2][3]. Since hydrogenation using molecular hydrogen is associated with risks and often requires high pressure apparatus, the alternative technique, CTH, has been employed in many laboratories. In transfer hydrogenation, several organic molecules such

Synthesis of (–)-Indolizidine 167B based on domino hydroformylation/cyclization reactions

• Giuditta Guazzelli,
• Raffaello Lazzaroni and
• Roberta Settambolo

Beilstein J. Org. Chem. 2008, 4, No. 2, doi:10.1186/1860-5397-4-2

• reaction mixture while the branched one 2b was in 13% (GC-MS control) with respect to the indolizine structure (Scheme 2). While at room temperature and high pressure the 2a/2b ratio is largely favorable to the branched aldehyde (29/71) [21], under the above conditions (high temperature and low pressure) a

• -tetrahydroindolizine 4 was obtained (Scheme 1; ii), together with the diastereoisomeric alcohols coming from the branched aldehyde: additional reduction of the pyrrole nucleus was never observed even by forcing the conditions (high pressure and high temperature). This goal was successfully reached by treating 4 (or 3

Photosonochemical catalytic ring opening of α-epoxyketones

• Hamid R. Memarian and
• Ali Saffar-Teluri

Beilstein J. Org. Chem. 2007, 3, No. 2, doi:10.1186/1860-5397-3-2

• were performed using a 400 W high pressure mercury lamp from Narva with cooling of samples in Duran glass. 1H NMR spectra of the mixture of photoproducts were measured in CDCl3 solutions containing tetramethylsilane (TMS) as internal standard on a Bruker drx-500 (500 MHz). Preparative layer