Biocatalytic oxidative kinetic resolution of sec-alcohols: stereocontrol through substrate-modification
摘要:
Whole lyophilised cells of Rhodococcus ruber DSM 44541 were employed for the oxidative kinetic resolution of sec-alcohols using acetone as hydrogen acceptor. The enantioselectivity of this process could be controlled effectively by introducing C-C multiple bonds into substrates, which were inefficiently recognised, in particular short-chain (omega-1)-alcohols and (omega-2)-analogs. Thus, the enantioselectivities of rac-2-pentanol (E= 16.8) and rac-3-octanol (E= 13.3) were significantly improved by introducing a C=C bond adjacent to the alcohol moiety to give racemic (E)-pent-3-en-2-ol and 4-(E)-octen-3-ol, which were resolved with excellent selectivities (E >100 and 50, respectively). In addition, it was found that high stereodifferentiation between the E- and Z-configured double bonds occurred, as the corresponding (Z)-isomers were not converted. Similar selectivity-enhancing effects were observed with acetylenic analogs. (C) 2003 Elsevier Science Ltd. All rights reserved.
Biocatalytic oxidative kinetic resolution of sec-alcohols: stereocontrol through substrate-modification
摘要:
Whole lyophilised cells of Rhodococcus ruber DSM 44541 were employed for the oxidative kinetic resolution of sec-alcohols using acetone as hydrogen acceptor. The enantioselectivity of this process could be controlled effectively by introducing C-C multiple bonds into substrates, which were inefficiently recognised, in particular short-chain (omega-1)-alcohols and (omega-2)-analogs. Thus, the enantioselectivities of rac-2-pentanol (E= 16.8) and rac-3-octanol (E= 13.3) were significantly improved by introducing a C=C bond adjacent to the alcohol moiety to give racemic (E)-pent-3-en-2-ol and 4-(E)-octen-3-ol, which were resolved with excellent selectivities (E >100 and 50, respectively). In addition, it was found that high stereodifferentiation between the E- and Z-configured double bonds occurred, as the corresponding (Z)-isomers were not converted. Similar selectivity-enhancing effects were observed with acetylenic analogs. (C) 2003 Elsevier Science Ltd. All rights reserved.
Abstract Allyl pyridyl ethers are important intermediates in organic synthesis, which could be accessed by Williamson or SNAr-type etherification. While Williamson etherification has been well studied, the SNAr-type reaction remains less explored. In this paper, a series of allyl pyridyl ethers were synthesized via transition metal-free SNAr-type etherification with different allylalcohols in good
Photodeoxygenation of Dibenzothiophene Sulfoxide: Evidence for a Unimolecular S−O Cleavage Mechanism<sup>1</sup>
作者:Daniel D. Gregory、Zehong Wan、William S. Jenks
DOI:10.1021/ja962975i
日期:1997.1.1
Photolysis of dibenzothiophene sulfoxide results in the formation of dibenzothiophene and oxidized solvent. Though quantum yields are low, chemical yields of the sulfide are quite high. Yields of the oxidized solvents can also be high. Typical products are phenol from benzene, cyclohexanol, and cyclohexene from cyclohexane and 2-cyclohexenol and epoxycyclohexane from cyclohexene. A number of experiments
Whole lyophilised cells of Rhodococcus ruber DSM 44541 were employed for the oxidative kinetic resolution of sec-alcohols using acetone as hydrogen acceptor. The enantioselectivity of this process could be controlled effectively by introducing C-C multiple bonds into substrates, which were inefficiently recognised, in particular short-chain (omega-1)-alcohols and (omega-2)-analogs. Thus, the enantioselectivities of rac-2-pentanol (E= 16.8) and rac-3-octanol (E= 13.3) were significantly improved by introducing a C=C bond adjacent to the alcohol moiety to give racemic (E)-pent-3-en-2-ol and 4-(E)-octen-3-ol, which were resolved with excellent selectivities (E >100 and 50, respectively). In addition, it was found that high stereodifferentiation between the E- and Z-configured double bonds occurred, as the corresponding (Z)-isomers were not converted. Similar selectivity-enhancing effects were observed with acetylenic analogs. (C) 2003 Elsevier Science Ltd. All rights reserved.