Enantioselective direct aldol reactions promoted by phosphine oxide aziridinyl phosphonate organocatalysts

A series of phosphine oxide based chiral Lewis bases were screened as organocatalysts for silicon tetrachloride mediated direct asymmetric aldol reactions between cyclohexanone and various aromatic aldehydes. One of the phosphine oxide-aziridinyl phosphonate POAP-A Lewis bases formed the aldol products in up to 75% yield and with 65% ee.


Spectroelectrochemistry of potassium ethylxanthate, bis(ethylxanthato)nickel(II) and tetraethylammonium tris(ethylxanthato)nickelate(II)
Dag, O; Yaman, SO; Önal, Ahmet Muhtar; Isci, H (2001-10-07)
Electrochemical and chemical oxidation of S2COEt-, Ni(S2COEt)(2), and [Ni(S2COEt)(3)](-) have been studied by CV and in situ UV-VIS spectroscopy in acetonitrile. Cyclic voltammograms of S2COEt- and Ni(S2COEt)(2) display one (0.00 V) and two (0.35 and 0.80 V) irreversible oxidation peaks, respectively, referenced to an Ag/Ag+ (0.10 M) electrode. However, the cyclic voltammogram of [Ni(S2COEt)(3)](-) displays one reversible (- 0.15 V) and two irreversible (0.35, 0.80 V) oxidation peaks, referenced to an Ag/Ag...
Enantioselective synthesis of both enantiomers of 2-amino-2-(2-furyl)ethan-1-ol as a flexible building block for the preparation of serine and azasugars
Demir, Ayhan Sıtkı; Sesenoglu, O; Aksoy-Cam, H; Kaya, H; Aydogan, K (Elsevier BV, 2003-05-16)
The selective conversion of 1-(2-furyl)-2-hydroxyethan-1-one and ethyl 2-(2-furyl)-2-oxo acetate into (E)- and (Z)-oximes and oxime ethers followed by oxazaborolidine-catalyzed enantioselective reduction using different amino alcohols furnished both enantiomers of the important chiral building block 2-amino-2-(2-furyl)ethan-1-ol with an ee of up to 96%.
Endohedrally halogen and interhalogen substituted C-70-AM1 study
Türker, Burhan Lemi (2002-12-09)
C-70 structure having a certain halogen (Cl-2, Br-2, I-2) or interhalogen molecule (BrCl, ICl, IBr) as the endohedral substituent was considered for semiempirical quantum chemical calculations at the level of AMI (RHF). All the endohedrally monosubstituted systems were found to be stable (inversely related to the bulkiness of the substituent) but endothermic (directly related to the size of the substituent). Some electronic and physicochemical properties of these systems were also reported.
Synthesis of selenophene substituted benzodithiophene and fluorinated benzothiadiazole based conjugated polymers for organic solar cell applications
Cevher, Duygu; Taşkaya Aslan, Sultan; Bolayır, Eda; Hizalan Ozsoy, Gonul; UDUM, YASEMİN; Yıldırım, Erol; Toppare, Levent Kamil; Çırpan, Ali (2021-12-01)
A series of alternating conjugated copolymers which contain selenophene modified benzodithiophene and fluorine bearing benzothiadiazole have been synthesized via Stille polycondensation reaction to investigate the effect of the number of fluorine atoms substituted to the benzothiadiazole. Three different polymers, PBDTSe-BT, PBDTSe-FBT and PBDTSe-FFBT, were reported and their electrochemical, spectroelectrochemical, and photovoltaic behaviors were examined. Density functional theory calculations were perfor...
Enantioselective synthesis of hydroxy ketones through cleavage and formation of acyloin linkage. Enzymatic kinetic resolution via C-C bond cleavage
Demir, Ayhan Sıtkı; Pohl, M; Janzen, E; Muller, M (2001-01-01)
Both enantiomers of benzoins and (R)-2-hydroxy-1-phenylpropanone analogues were obtained in high yield on a preparative scale starting from aromatic aldehydes, rac-benzoins and aliphatic aldehydes via enzyme-catalysed C-C bond cleavage and C-C bond formation reactions.
Citation Formats
Ö. Doğan, “Enantioselective direct aldol reactions promoted by phosphine oxide aziridinyl phosphonate organocatalysts,” TETRAHEDRON-ASYMMETRY, pp. 1348–1353, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36492.