Search results
Search for "α,β-unsaturated ketones" in Full Text gives 84 result(s) in Beilstein Journal of Organic Chemistry.
Efficient gold(I)/silver(I)-cocatalyzed cascade intermolecular N-Michael addition/intramolecular hydroalkylation of unactivated alkenes with α-ketones
Beilstein J. Org. Chem. 2011, 7, 1100–1107, doi:10.3762/bjoc.7.126
- /intramolecular hydroalkylation reaction. The present protocol with a dual-metal catalytic system provides a highly efficient method for the synthesis of a variety of pyrrolidine compounds in moderate to excellent product yields and with moderate to good diastereoselectivities from α,β-unsaturated ketones and
Synthetic applications of gold-catalyzed ring expansions
Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87
- such as 15, reported in 2007 by Chung and co-workers [21], led to a completely different outcome (Scheme 5). This transformation did not lead to the expected cyclopentanones. Instead, α,β-unsaturated ketones 16 were isolated in good yields. The proposed mechanism (Scheme 5) involves nucleophilic attack
Gold-catalyzed regioselective oxidation of terminal allenes: formation of α-methanesulfonyloxy methyl ketones
Beilstein J. Org. Chem. 2011, 7, 596–600, doi:10.3762/bjoc.7.69
- toxic and potentially explosive α-diazo ketones (Scheme 1A). Synthetically useful structures such as oxetan-3-ones [22], dihydrofuran-3-ones [23], azetidin-3-ones [24] and α,β-unsaturated ketones [25] are readily accessed via these gold carbene intermediates. This led us to consider whether or not
Asymmetric synthesis of tertiary thiols and thioethers
Beilstein J. Org. Chem. 2011, 7, 582–595, doi:10.3762/bjoc.7.68
- demonstrated by the catalytic asymmetric additions of thiols to α,β-unsaturated ketones [44]. (R)-LaNa3tris(binaphthoxide) (LSB) catalyses asymmetric addition to cyclic enones (Scheme 16), and products of addition 43 are isolated in good yields and enantiomeric ratios. However, addition to the substituted
Rh(I)-catalyzed intramolecular [2 + 2 + 1] cycloaddition of allenenes: Construction of bicyclo[4.3.0]nonenones with an angular methyl group and tricyclo[6.4.0.01,5]dodecenone
Beilstein J. Org. Chem. 2011, 7, 404–409, doi:10.3762/bjoc.7.52
- the α,β-unsaturated ketones 2. By taking advangage of this newly developed reaction, we have completed the first total syntheses of two tricyclic sesquiterpenes 6a,b, isolated from Jatropha neopauciflora, from the methoxycarbonylallenene 4 via the bicyclo[4.3.0]nonenone derivative 5 [24]. The key step
An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives
Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66
- ]pyridazines through a hitherto unprecedented approach from a BOC-protected 1-aminopyrrole derivative and α,β-unsaturated ketones. Results and Discussion 2-[2-(4-Fluorophenyl)-2-oxo-1-phenylethyl]-4-methyl-3-oxo-pentanoic acid phenylamide 1 was reacted with tertiary butyl carbazate 2 in toluene and cyclohexane
- and subsequent decarboxylation was carried out on pyrrole derivative 15 to afford the 2,3-diaryl pyrrole derivative 16 (Scheme 3). With a view to extending this protocol to aliphatic systems such as α,β-unsaturated ketones, carbamate 3 was treated with crotonaldehyde under similar conditions. However
Efficient 1,4-addition of α-substituted fluoro(phenylsulfonyl)methane derivatives to α,β-unsaturated compounds
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
Multiple hydride reduction pathways in isoflavonoids
Beilstein J. Org. Chem. 2006, 2, No. 16, doi:10.1186/1860-5397-2-16
- , and their estrogenic and other physiological properties, making them promising lead compounds for drug design. Results The reduction of isoflavones by various hydride reagents occurs by a 1,4-pathway in contrast to ordinary β-alkoxy-α,β-unsaturated ketones. Isoflavan-4-ones, cis- and trans-isoflavan-4
- reagents have been tested, as discussed below, for the reduction of simple or protected isoflavones but many of the early results are contradictory or rely on indeterminate product characterization. The reduction of simple (nonflavonoid) β-alkoxy-α,β-unsaturated ketones by hydride reagents (NaBH4, LiAlH4
- reductions, must reflect the good stabilization obtainable via resonance heteroring stabilization (10) in the isoflavones. As already mentioned, this is in contrast to the behaviour of simple non-flavonoid β-alkoxy-α,β-unsaturated ketones which prefer 1,2-attack by hydride. Isoflavenes (7, 8) and isoflavans
A convenient synthesis of γ-functionalized cyclopentenones
Beilstein J. Org. Chem. 2005, 1, No. 11, doi:10.1186/1860-5397-1-11
- conjugate addition of nitroalkanes to α,β-unsaturated ketones 1 leading to the nitroalkanes derivatives 2 which may be converted into their γ-diketone homologues 3 using Nef reaction. The intramolecular cyclization of 1,4-diketones 3 led to the corresponding cyclopentenones 4. Results and discussion As
- previously reported, the 1,4-addition of primary nitroalkanes [7][8][9][10][11][12] to functionalized α,β-unsaturated ketones was considered as an appropriate method to prepare multifunctional nitroketonic compounds. These intermediates are important in organic synthesis because the nitro group can be
- converted into other useful groups such as amines or carbonyls.[13][14] Treatment of α,β-unsaturated ketones 1[15] with primary nitroalkanes was achieved by refluxing the mixture at 50°C in THF using sodium methoxide as base (Scheme 1), resulting in full conversion and yielding the Michael adducts 2 (Table
Other Beilstein-Institut Open Science Activities
