The reaction was stirred out at room temperature until completion and was quenched by the addition of ammonium hydroxide. The enatiopure epoxide is converted further to (S)-chromanemethanol, which is a chiral building block for enantiopure vitamin D.83, Kohei Oda, in Handbook of Proteolytic Enzymes (Third Edition), 2013. Inactivation of the 3-methylcatechol 2,3-dioxygenase gene (todE) in P. putida S7 did not prevent growth on styrene, and a second catechol 2,3-dioxygenase gene similar to dmpB (from the phenol degradation pathway in Pseudomonas sp. 0000070713 00000 n
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Further process improvements have been realized with the third and fourth generation oligo(salen) catalysts, which have led to improved economy and productivity for the overall process. However, much like the HKR of epichlorohydrin, a more significant problem was encountered when scaling the HKR of styrene oxide involving the racemization and decomposition of the resolved epoxide during isolation. A similar pathway for styrene degradation appears to be present in R. jostii RHA1 [156]. Reaction profile of the infrared absorbances obtained during the ring-opening polymerization from the end-capped OH of poly(styrene carbonate) in the presence of DBU and lactide. First, the epoxide could undergo Lewis acid-catalyzed rearrangement to phenylacetaldehyde in the presence of strongly Lewis acidic complexes such as 1d. One-pot synthesis of campholenic aldehyde from α-pinene has been achieved using t-butyl hydroperoxide and a Ti-containing mesoporous material of the HMS-type [80]. M. Schallmey, ... D.B.
For example, the rabbit sEH exhibits a regioselectivity of 45%(C1):55%(C2) for conversion of SSO,84 while for the Aspergillus niger EH, it is 15%(C1):85%(C2).86 Exclusive attack at the benzylic carbon of SSO is mediated by the Beauveria sulfurescens EH86 while EchA from A. radiobacter AD1 seems to mediate exclusive attack at the terminal carbon.78 The potato Solanum tuberosum StEH converts styrene oxide in an enantioconvergent manner, with preferred attack at C1 for SSO (98%) and preferred attack at C2 for RSO (92%).87 A possible explanation of the experimental variations in regioselectivity can be given based on the computed energetics.
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In 2004, a second generation Lewis base was identified for the stabilization of the styrene oxide HKR reaction medium, which allowed for the routine production of (R)-styrene oxide (or analogs) in >250 kg batches and >70% isolated yield (typical chiral purity specification is 98% ee, but can be optimized to >99% ee).