153630-80-9Relevant academic research and scientific papers
Enantioselective Vicinal Diacetoxylation of Alkenes under Chiral Iodine(III) Catalysis
W?ste, Thorsten H.,Mu?iz, Kilian
, p. 816 - 827 (2016/03/15)
A procedure for the intermolecular enantioselective dioxygenation of alkenes under iodine(III) catalysis has been developed. This protocol employs Selectfluor as the terminal oxidant together with a defined C 2-symmetric aryl iodide as the organocatalyst. This enantioselective reaction proceeds under mild conditions and converts a series of terminal and internal styrenes into the corresponding vicinal diacetoxylation products with up to 96% ee.
Structurally Defined Molecular Hypervalent Iodine Catalysts for Intermolecular Enantioselective Reactions
Haubenreisser, Stefan,W?ste, Thorsten H.,Martnez, Claudio,Ishihara, Kazuaki,Muiz, Kilian
, p. 413 - 417 (2016/01/25)
Molecular structures of the most prominent chiral non-racemic hypervalent iodine(III) reagents to date have been elucidated for the first time. The formation of a chirally induced supramolecular scaffold based on a selective hydrogen-bonding arrangement provides an explanation for the consistently high asymmetric induction with these reagents. As an exploratory example, their scope as chiral catalysts was extended to the enantioselective dioxygenation of alkenes. A series of terminal styrenes are converted into the corresponding vicinal diacetoxylation products under mild conditions and provide the proof of principle for a truly intermolecular asymmetric alkene oxidation under iodine(I/III) catalysis.
Sharpless asymmetric dihydroxylation as the key step in the enantioselective synthesis of spirocyclic σ1 receptor ligands
Holl, Katharina,Schepmann, Dirk,Daniliuc, Constantin Gabriel,Wuensch, Bernhard
, p. 268 - 277 (2014/03/21)
The enantioselective synthesis of fluorinated spirocyclic σ1 ligands involved three key steps: (1) the Sharpless asymmetric dihydroxylation of 2-bromostyrene 5 provided enantiomerically pure diols (R)-6 and (S)-6 establishing the stereogenic center; (2) the intramolecular opening of the oxirane ring of (R)-11 and (S)-11, which occurred with excellent regioselectivity and complete inversion of configuration giving access to enantiomerically pure alcohols (S)-7a and (R)-7a; (3) the treatment of alcohols (S)-7b and (R)-7b with DAST, which led to the fluoromethyl derivatives (S)-1 and (R)-1 without racemization. X-ray crystal structure analysis of the tosylate (R)-13 confirmed the absolute configuration of the spirocyclic compounds as well as the enantioselectivity during the Sharpless asymmetric dihydroxylation of 5. The (S)-configured fluoromethyl derivative (S)-1 revealed a high σ1 affinity (Ki = 1.8 nM), high eudismic ratio (factor 8) and high selectivity over the σ2 subtype (667-fold).
Asymmetric diboration of terminal alkenes with a rhodium catalyst and subsequent oxidation: Enantioselective synthesis of optically active 1,2-diols
Toribatake, Kenji,Nishiyama, Hisao
supporting information, p. 11011 - 11015 (2013/10/22)
Pin it down: A highly enantioselective diboration of terminal alkenes with chiral 1 and bis(pinacolato)diboron (B2pin2) was realized. Subsequent oxidation of the diboron adducts with sodium peroxoborate readily gave the corresponding optically active 1,2-diols in high yields and high enantioselectivities. Copyright
Enantioselective hydrolysis of various substituted styrene oxides with Aspergillus Niger CGMCC 0496
Jin, Hao,Li, Zu-Yi,Dong, Xiao-Wei
, p. 408 - 414 (2007/10/03)
Enantioselective biohydrolysis of various substituted styrene oxides using whole fungus cells of Aspergillus niger CGMCC 0496 are described. The results show not only para- but also some ortho- substituted styrene oxides can achieve high enantioselectivity during the hydrolysis.
New and efficient chiral selenium electrophiles
Uehlin, Lars,Fragale, Gianfranco,Wirth, Thomas
, p. 1125 - 1133 (2007/10/03)
New chiral diselenides were prepared in a few steps from readily available starting materials. The selenium electrophiles generated from these diselenides were used for the efficient stereoselective inter- and intramolecular functionalization of alkenes. The substitution pattern influences the stereoselectivities and protection of the hydroxy moiety in the chiral side chain led to increased selectivities and yields in the selenenylation reactions. An additional substituent in the second ortho position was advantageous as well. Addition products with up to 96% de were obtained. The influence of the nucleophile on the outcome of selenenylations of alkenes was studied to some extent as well.
MICROBIAL OXIDATION OF 2-BROMOSTYRENE BY PSEUDOMONAS PUTIDA 39/D. ISOLATION AND IDENTIFICATION OF METABOLITES
Koenigsberger, Kurt,Hudlicky, Tomas
, p. 2468 - 2474 (2007/10/02)
2-Bromostyrene was subjected to microbial oxidation by two microorganisms.Oxidation by Pseudomonas putida 39/D yielded a mixture of ring dihydroxylated (1S,2R)-4-bromo-3-ethenylcyclohexa-3,5-diene-1,2-diol (4a) (optical purity o.p.>92percent) and side cha
