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Search for "carboxylation" in Full Text gives 58 result(s) in Beilstein Journal of Organic Chemistry.
Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes
Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198
- cyclization of alkenylindoles by Pd(II) catalysis under carbonylative conditions [81][82]. This approach, based on the use of copper(II) chloride as oxidant, has been applied to 2- and 3-alkenylindoles, resulting in a domino process that involves an alkenylation/carboxylation sequence (Scheme 23). Thus
- alkenylation/carboxylation sequence was successfully performed by reaction of styrene compounds with 2-substituted indoles to give 3-benzylindoles bearing an ester group (Scheme 24). It should be pointed out that the presence of a functional group at the C-2 indolyl position is essential to obtain a
- . The subsequent transfer of carbon monoxide with stereochemical retention determines the generation of the σ-acyl-palladium complex XVIII, which in turn is converted in the final cis-substituted tetrahydrocarbazole by methanolysis giving the carboxylation step. Again, the released Pd(0) species
Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca
Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200
- from [2H5]sodium propionate is in agreement with the biosynthesis of FAs (Scheme 1): One deuterium is lost during carboxylation of propionyl-CoA to yield methylmalonyl-CoA, the second is possibly exchanged with water due to the C,H-acidity of malonyl-CoA derivatives, but it is lost, at the latest, in
Structural conditions required for the bridge lithiation and substitution of a basic calix[4]arene
Beilstein J. Org. Chem. 2011, 7, 1602–1608, doi:10.3762/bjoc.7.188
- the lower-rim site as well as tert-butylated or non-tert-butylated upper-rim positions. Whereas this reaction fails for symmetric calix[4]arene ethers with alkoxy residues greater than methoxy, the carboxylation of mixed methoxy-propoxy calixarene ethers is possible. In connection with this, several
- undergo lithiation and subsequent carboxylation to yield the carboxylic acid 6 [4], we became interested in the question of whether the upper-rim unsubstituted calix[4]arene 1, as well as higher ether homologues, such as 3 and 4, can also be used for this reaction (Scheme 1). While the upper-rim site
Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series
Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187
- regioselective functionalization. Ortho-lithiation by means of alkyllithium and lithium amides bases has been extensively developed as lithiated species display a high reactivity towards many electrophiles, leading to various substitutions (e.g., halogenation, carboxylation, acylation, hydroxymethylation
Directed aromatic functionalization in natural-product synthesis: Fredericamycin A, nothapodytine B, and topopyrones B and D
Beilstein J. Org. Chem. 2011, 7, 1475–1485, doi:10.3762/bjoc.7.171
- methodology. Thus, ortho-deprotonation of diethylamide 16 (Scheme 3) and carboxylation afforded anhydride 17 directly after workup with 12 N aqueous HCl. Fischer esterification and condensation of the resultant 18 with diethyl succinate, according to Kelly [6][7], afforded 19, which was then elaborated to a 1
Scalable synthesis of (1-cyclopropyl)cyclopropylamine hydrochloride
Beilstein J. Org. Chem. 2011, 7, 1003–1006, doi:10.3762/bjoc.7.113
- degradation [19][20]. Results and Discussion Preparation of the acid 2 from the known 1-bromo-1-cyclopropylcyclopropane (1) [21][22] according to the published procedure [17] was accomplished on a 100 g scale (Scheme 1). However, the yield of the carboxylation on a scale of 12.4 mmol, 900 mmol and 1400 mmol
The role of silver additives in gold-mediated C–H functionalisation
Beilstein J. Org. Chem. 2011, 7, 892–896, doi:10.3762/bjoc.7.102
- a carboxylation reaction [12] with substrate 2 using catalyst 1 under optimised carboxylation conditions (Scheme 3). The general procedure employed 2, 1 (3 mol %), Ag2O (3 mol %) and three equivalents of potassium hydroxide. Gratifyingly, whereas a reaction in the absence of silver leads to no
- carboxylation product, the addition of silver leads to formation of 2,4,6-trifluorobenzoic acid (5). The use of a stoichiometric amount of Ag2O results in aggregation of the reagents that seemingly affects mass transport of CO2 and halts the reaction. However, the catalytic use of Ag2O gave a 22% isolated yield
- of 5. This observation clearly shows that silver can have a positive role in the carboxylation of C–H bonds. Conclusion The C–H functionalisation of arenes using (NHC)gold(I) complexes has been shown to be significantly affected by the leaving group on the gold. The gold(I) chloride may only react by
Trifluoromethyl ethers – synthesis and properties of an unusual substituent
Beilstein J. Org. Chem. 2008, 4, No. 13, doi:10.3762/bjoc.4.13
- lithiation next to the OCF3 substituent is favoured, probably due to steric reasons. In fact, 1-trifluoromethoxy-4-(trifluoromethyl)benzene (Scheme 15) affords 2-trifluoromethoxy-5-(trifluoromethyl)benzoic acid after lithiation and carboxylation [75]. When the OCF3 substituent is in competition with fluorine
- metalation with tert-butyllithium, followed by carboxylation (Scheme 20) [71]. When the amino function is protected instead of a BOC group by a silyl group, 3-trifluoromethoxy-N-(trimethylsilyl)aniline is metalated in position 2. However, 3- and 4-trifluoromethoxy-N,N-bis(trimethylsilyl)aniline are metalated
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