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pro vyhledávání: '"H.‐J. Gais"'
Acetylenes having both electrondonating and electronaccepting groups (1) may be obtained in good yield from the correspondingly substituted olefines via bromination and elimination of HBr. The reaction of the acetylene aldehyde 1a with proton acids y
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::699d083ab356784ebd70e1d30a1d3ccf
http://tuprints.ulb.tu-darmstadt.de/22406/
http://tuprints.ulb.tu-darmstadt.de/22406/
Autor:
H.‐J. Gais
Publikováno v:
Heteroatom Chemistry. 18:472-481
Sulfoximine-substituted bis(allyl)titanium complexes, which are configurationally labile at the Cα-atoms, have emerged as valuable reagents in asymmetric synthesis. Their highly selective reactions with aldehydes and N-sulfonyl imino esters allow th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3de933afb7590b86e51d64c26dad9487
https://doi.org/10.1002/hc.20331
https://doi.org/10.1002/hc.20331
Publikováno v:
Zeitschrift für Naturforschung A. 59:124-132
3 The chiroptical properties of the diastereomeric alcohols (E)-(3S,4S)-4-methyl-1-tributylstannyloct- 1-en-6-yn-3-ol ((S,S)-) and (E)-(3R,4S)-4-methyl-1-tributylstannyl-oct-1-en-6-yn-3-ols ((R,S)- 3) have been studied experimentally as well as by qu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::7c42c244d0071a88711b3c21ef0e9fa9
https://doi.org/10.1515/zna-2004-0305
https://doi.org/10.1515/zna-2004-0305
Publikováno v:
European Journal of Organic Chemistry. 1998:805-826
Asymmetric total syntheses of 3-oxacarbacyclin (4) and 3-oxaisocarbacyclin (5) have been achieved by a new and common route. The key step of these syntheses is an enantioselective deprotonation of the prochiral ketone 25 with lithium (R,R)-bis(phenyl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3bb9338351df5157d0960a784a1a34b5
https://doi.org/10.1002/(sici)1099-0690(199805)1998:5<805::aid-ejoc805>3.0.co
https://doi.org/10.1002/(sici)1099-0690(199805)1998:5<805::aid-ejoc805>3.0.co
Autor:
H.‐J. Gais, Michael Frank, Frank Gerhards, Holger Eichelmann, Gerhard Raabe, Nicole Spalthoff
Publikováno v:
Tetrahedron: Asymmetry. 9:235-248
The acyclic and cyclic allylic tert -butyl sulfones 3 , ent - 3 , 11a , 11b and 15a–c of 89–98% ee were synthesized in 40–92% yield by a Pd-catalyzed reaction of the respective allylic acetates and carbonates rac - 1a , rac - 1b , rac - 10a , r
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1e78708c1d2920f5c08e49618a6acb3b
https://doi.org/10.1016/s0957-4166(97)00601-0
https://doi.org/10.1016/s0957-4166(97)00601-0
Autor:
Stephan Ruppert, H.‐J. Gais
Publikováno v:
Tetrahedron: Asymmetry. 8:3657-3664
Colyophilization of pig liver esterase with methoxypolyethylene glycol gave a catalyst, PLE/MPEG, which showed an enhanced activity in organic solvents. The PLE/MPEG catalyzed transesterification of the alcohols rac- 1a–d with vinyl propionate in t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::6712c39b368f95bd3fc63291acd82d99
https://doi.org/10.1016/s0957-4166(97)00469-2
https://doi.org/10.1016/s0957-4166(97)00469-2
Autor:
H.‐J. Gais, Jochen R. Brandt
Publikováno v:
Tetrahedron: Asymmetry. 8:909-912
Racemic S-methyl-S-phenylsulfoximine (±)-1 can be resolved with only 0.6 equivalents of (+)-camphorsulfonic acid by avoiding any recrystallization to give (+)-1 of ⩾99% ee in 80% yield and (−)-1 of 97–99% ee in 74% yield. This procedure, which
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::19b390b1956c53f7ec8b9b02db243ae7
https://doi.org/10.1016/s0957-4166(97)00046-3
https://doi.org/10.1016/s0957-4166(97)00046-3
Publikováno v:
Tetrahedron: Asymmetry. 7:2505-2508
Titanation of the lithioallyl sulfoximines E-2 and Z-2 with ClTi(NEt2)3 gives allyltitanium species which react with aldehydes highly regio- and diastereoselectively at the α-position to form the syn-α-hydroxyalkyl allyl sulfoximines E-3 and Z-3, r
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::12a7edb2d5fcd9d46e615c898ebbfc7d
https://doi.org/10.1016/0957-4166(96)00318-7
https://doi.org/10.1016/0957-4166(96)00318-7
Autor:
H.‐J. Gais, Ludger Heiss
Publikováno v:
Tetrahedron Letters. 36:3833-3836
MPEG-PLE was prepared by modification of PLE with 1 and characterized by gel electrophoresis, size exclusion chromatography, anion exchange chromatography and photon correlation spectroscopy. It retains the activity of native PLE in the enantioselect
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::10b167779ab554f15edf3fe85adeae22
https://doi.org/10.1016/0040-4039(95)00631-l
https://doi.org/10.1016/0040-4039(95)00631-l
Autor:
H.‐J. Gais, Holger Eichelmann
Publikováno v:
Tetrahedron: Asymmetry. 6:643-646
The palladium-catalyzed asymmetric sulfonylation of allylic substrates rac- 7a,b and rac- 8a,b in the presence of the chiral phosphino-oxazoline ligand 3a gave the allylic sulfones 9a and 9b with ee-values of 59% and 88%, respectively, in high yield.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::18bcfe76b2306915683429c84715047b
https://doi.org/10.1016/0957-4166(95)00049-u
https://doi.org/10.1016/0957-4166(95)00049-u