Radical carbonylations using a continuous microflow system

• Takahide Fukuyama,
• Md. Taifur Rahman,
• Naoya Kamata and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2009, 5, No. 34, doi:10.3762/bjoc.5.34

• acyl radical traps (entries 6 and 7 ). Gratifyingly, in both cases, good yields of the three-component coupling products were formed by using reduced CO pressure. Conclusion We have developed a facile platform to conduct radical carbonylation under CO pressure in a flow system comprised of a T-shaped

Part 3. Triethylborane- air: a suitable initiator for intermolecular radical additions of S-2-oxoalkyl- thionocarbonates (S-xanthates) to olefins

• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 47, doi:10.1186/1860-5397-3-47

• ][10][11][12][13][14] Trapping with benzaldehyde gave aldol 1d (48%, Scheme 1) and thus confirmed that a boron enolate is a plausible intermediate in the reduction of compound 1a into 1b. One cannot put aside the possibility that the reduction of the transient α-acyl radical may also occur, to a minor

• in which Et3B is implicated not only in the generation of the α-acyl radical but also in the reaction with the latter, in a stoichiometric manner, to afford an intermediate boron enolate. Lowering the amount of Et3B would therefore minimise the premature unwanted reduction. This hypothesis was then

• to stabilised radical B. The latter fragments either to xanthate A and Et• or, more easily, to stabilised α-acyl radical C and dithiocarbonate D. From the intermediate radical C, three possible routes determine the outcome of the reaction. Route a1 represents the xanthate group transfer between

Do α-acyloxy and α-alkoxycarbonyloxy radicals fragment to form acyl and alkoxycarbonyl radicals?

• Dennis P. Curran and
• Tiffany R. Turner

Beilstein J. Org. Chem. 2006, 2, No. 10, doi:10.1186/1860-5397-2-10

• fragmentation of radical 13a to release an acyl radical 16a. However, the ratios of 15/14a do not fit well with the standard model of competing unimolecular (fragmentation) and bimolecular (reduction) reactions in Figure 4. For example, the 10-fold dilution in going from entry 4 to entry 5 should have resulted