Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

• Andreas Speicher,
• Timo Backes,
• Kerstin Hesidens and
• Jürgen Kolz

Beilstein J. Org. Chem. 2009, 5, No. 71, doi:10.3762/bjoc.5.71

• benzylic alcohol 20 [28]. Protection as the THP acetal 21 was essential before preparing the boronic acid 22. Previously (see [15]), we reported on a synthesis of 22 starting with the bromination of 3-methoxybenzyl alcohol to 4-bromo-3-methoxybenzyl alcohol. In contrast to the original contribution [29

Hydrogenation of aromatic ketones, aldehydes, and epoxides with hydrogen and Pd(0)EnCat™ 30NP

• Steven V. Ley,
• Angus J. P. Stewart-Liddon,
• David Pears,
• Remedios H. Perni and
• Kevin Treacher

Beilstein J. Org. Chem. 2006, 2, No. 15, doi:10.1186/1860-5397-2-15

• -methoxyacetophenone are summarized in Table 1. In the first case, when Pd/C was used the over-reduced product was quantitatively obtained (entries 7 and 8). Using palladium on different supports with lower surface area than carbon, such as CaCO3 or Al2O3 (entries 4 and 5) a mixture of benzylic alcohol and over

• efficiently for this electron rich aromatic system. [17][18] To explore the scope of this reaction, different electron rich and electron deficient aldehydes were also tested under these standard conditions using Pd(0)EnCat™ 30NP as a catalyst. In general good conversions to the corresponding benzylic alcohol

• were obtained. The results are summarized in Table 2. trans-Stilbene oxide was chosen as a model for the hydrogenolysis of aromatic epoxides. The effect of different heterogeneous palladium catalysts and their propensity to over-reduce the benzylic alcohol generated after hydrogenolysis of the epoxide