Enantioselective α-Arylation of Carbonyls via Cu(I)-Bisoxazoline Catalysis
摘要:
The enantioselective alpha-arylation of both lactones and acyl oxazolidones has been accomplished using a combination of diaryliodonium salts and copper catalysis. These mild catalytic conditions provide a new strategy for the enantioselective construction and retention of enolizable alpha-carbonyl benzylic stereocenters, a valuable synthon for the production of medicinal agents.
Amine Catalysis with Substrates Bearing
<i>N</i>
‐Heterocyclic Moieties Enabled by Control over the Enamine Pyramidalization Direction
作者:Jasper S. Möhler、Tobias Schnitzer、Helma Wennemers
DOI:10.1002/chem.202002966
日期:2020.12
Stereoselective organocatalytic C−C bond formations that tolerate N‐heterocycles are valuable since these moieties are common motifs in numerous chiral bioactive compounds. Such transformations are, however, challenging since N‐heterocyclic moieties can interfere with the catalytic reaction. Here, we present a peptide that catalyzes conjugateaddition reactions between aldehydes and nitroolefins bearing a
Methylene blue catalyzes the visible light-induced organocatalytic α-oxyamination of aldehydes via enamines. The irradiation of 3-phenylpropanal with TEMPO radical in the presence of morpholine as an organocatalyst and methylene blue as a photoredox catalyst gave the desired α-functionalized aldehyde in 75% yield.
亚甲蓝通过烯胺催化可见光诱导的醛的有机催化 α-氧胺化。在作为有机催化剂的吗啉和作为光氧化还原催化剂的亚甲蓝存在下,用 TEMPO 自由基对 3-苯基丙醛进行辐照,以 75% 的产率得到所需的 α-官能化醛。
Enantioselective Organocatalytic Conjugate Addition of Aldehydes to Vinyl Sulfones and Vinyl Phosphonates as Challenging Michael Acceptors
Chiral framework: Chiral amines with pyrrolidine frameworks catalyze the enantioselective conjugate addition of a wide range of aldehydes to various vinyl sulfones and vinyl phosphonates in high yields and with enantioselectivities up to >99 % ee (see scheme). The high versatility of the Michael adducts is exemplified by various functionalizations with conservation of the optical purity.
Easy Access to Aroma Active Unsaturated γ-Lactones by Addition of Modified Titanium Homoenolate to Aldehydes
作者:Eric Frerot、Alain Bagnoud
DOI:10.1021/jf104711x
日期:2011.4.27
The homo-Reformatsky reaction, in which a metalhomoenolate of an ester is added to an aldehyde, was adapted to produce γ-lactones from unsaturated, enolizable aldehydes. By use of titaniumhomoenolate, 11 different γ-lactones were synthesized in one step with moderate to good yields from readily available aldehydes. In particular, this procedure allowed the rapid preparation of a series of C12 unsaturated
1,2-Sulfone rearrangement in organocatalytic reactions
作者:Adrien Quintard、Alexandre Alexakis
DOI:10.1039/c0ob00818d
日期:——
The 1,2-sulfone rearrangement resulting from nucleophilic addition to bis activated vinyl-sulfones has been studied in more detail. Various nucleophiles activated by different types of catalysts (enamine, Brönsted base, thiourea) are able to promote such rearrangement in excellent yields and moderate to excellent enantioselectivities (up to 94% ee). Mechanistic studies have led to a better understanding of the mechanism and allowed its application to other electrophiles such as vinyl-sulfone acrylates.