132016-57-0Relevant academic research and scientific papers
Aminooxylation Horner-Wadsworth-Emmons Sequence for the Synthesis of Enantioenriched γ-Functionalized Vinyl Sulfones
Doherty, William,Evans, Paul
supporting information, p. 1416 - 1424 (2016/03/01)
An operationally simple protocol for the synthesis of γ-hydroxy vinyl sulfones has been developed using a proline-based aldehyde aminooxylation, followed by a vinyl sulfone forming Horner-Wadsworth-Emmons olefination. The adducts, formed in high enantiopurity, were subsequently converted to γ-azido vinyl sulfones, and azide-alkyne click chemistry enabled the synthesis of vinyl sulfone-based triazoles as potential nonpeptidic cysteine protease inhibitors. (Chemical Equation Presented).
Palladium-catalyzed asymmetric synthesis of allylic alcohols from unsymmetrical and symmetrical racemic allylic carbonates featuring C-O-bond formation and dynamic kinetic resolution
Gais, Hans-Joachim,Bondarev, Oleg,Hetzer, Ralf
, p. 6279 - 6283 (2007/10/03)
Described is the asymmetric synthesis of the allylic alcohols 11 (85% ee), 15 (99% ee), 17 (93% ee), 19 (61% ee), and 21 (69% ee) through a Pd-catalyzed reaction of the unsymmetrical carbonates rac-10, rac-12, rac-14, rac-16, rac-18, and rac-20, respectively, with KHCO3 and H2O in the presence of bisphosphane 6. Similarly the allylic alcohols 23 (99% ee) and 25 (97% ee) have been obtained from the symmetrical carbonates rac-22 and rac-24, respectively. Reaction of the meso-biscarbonate 26 with H2O and Pd(0)/6 afforded alcohol 27 (96% ee), which was converted to the PG building block 32. The unsaturated bisphosphane 33 showed in the synthesis of alcohols 36, 37, and 39 a similar high selectivity as 6. The formation of alcohols 11, 15, and 17 involves an efficient dynamic kinetic resolution.
Lipase-Catalyzed Kinetic Resolution of γ-Hydroxy Phenyl Sulfones
Carretero, Juan C.,Dominguez, Esteban
, p. 3867 - 3873 (2007/10/02)
Lipase PS (from Pseudomonas cepacia) catalyzed the enantioselective transesterification of racemic γ-hydroxy-α,β-unsaturated phenyl sulfones 1 and their α,β-saturated derivatives 3 with vinyl acetate in an organic solvent (usually iPr2O).Remarkably, in substrates 1 with (E)-stereochemistry, the enantioselectivity of the process was little influenced by the nature of the R chain.Hence, very high enantiomeric ratios (E>/=45) were observed in substrates 1 bearing short (R = Me or Et), long (R = n-C6H13 or n-C10H21), bulky (R = iPr), or functionalized R chains.The (R)-enantiomer was the fast-reacting enantiomer in all cases.Concerning the reactivity, the rate of the reaction decreased significantly with an increase in size of length of the R chain (reaction time for 50percent conversion from 3.5 to 162 h).Less satisfactory enantioselectivities (E = 5-48) were obtained when the saturated substrates 3 were used instead of the corresponding α,β-unsaturated alcohols 1.
AN EFFICIENT PREPARATION OF OPTICALLY ACTIVE (E)-γ-HYDROXY-α,β-UNSATURATED PHENYL SULFONES USING LIPASE-MEDIATED ACYLATIONS
Dominguez, Esteban,Carretero, Juan Carlos,Fernandez-Mayoralas, Alfonso,Conde, Santiago
, p. 5159 - 5162 (2007/10/02)
(E)-γ-Hydroxy-α,β-unsaturated phenyl sulfones have been efficiently resolved via irreversible enzymatic acylation with Lipase PS (Pseudomonas cepacia) and vinyl acetate.This process has been applied to the synthesis of the aggregation pheromone (-)-(3S,4S)-4-methyl-3-heptanol.
