Chemoenzymatic Asymmetric Synthesis of Pregabalin Precursors via Asymmetric Bioreduction of β-Cyanoacrylate Esters Using Ene-Reductases
摘要:
The asymmetric bioreduction of a library of beta-cyanoacrylate esters using ene-reductases was studied with the aim to provide a biocatalytic route to precursors for GABA analogues, such as pregabalin. The stereochemical outcome could be controlled by substrate-engineering through size-variation of the ester moiety and by employing stereochemically pure (E)- or (Z)-isomers, which allowed to access both enantiomers of each product in up to quantitative conversion in enantiomerically pure form. In addition, stereoselectivities and conversions could be improved by mutant variants of OPR1, and the utility of the system was demonstrated by preparative-scale applications.
Palladium-Catalyzed Cross-Coupling Reaction of Bis(pinacolato)diboron with 1-Alkenyl Halides or Triflates: Convenient Synthesis of Unsymmetrical 1,3-Dienes via the Borylation-Coupling Sequence
1-alkenylboronic acid pinacol esters via a palladium-catalyzed cross-coupling reaction of bis(pinacolato)diboron (pin(2)B(2), pin = Me(4)C(2)O(2)) with 1-alkenyl halides or triflates was carried out in toluene at 50 degrees C in the presence of KOPh (1.5 equiv) and PdCl(2)(PPh(3))(2)-2Ph(3)P (3 mol %). The borylation of acyclic and cyclic 1-alkenyl bromides and triflates was achieved in high yields with complete
Palladium-Catalyzed Synthesis of <i>N</i>-Vinyl Pyrroles and Indoles
作者:Mohammad Movassaghi、Alison E. Ondrus
DOI:10.1021/jo051450i
日期:2005.10.1
azaheterocycles with vinyl triflates is described. Cyclic and acyclic vinyl triflates along with nonnucleophilic azaheterocycles were found to be substrates for this palladium-catalyzed synthesis of N-vinyl pyrrole and indole derivatives.
Stereocontrolled Synthesis of the cis-Hydroxydecalin System: Towards Biologically Active 19-nor-Clerodanes
作者:Paul Malek Mirzayans、Rebecca H. Pouwer、Craig M. Williams、Paul V. Bernhardt
DOI:10.1002/ejoc.201101807
日期:2012.3
The 19-nor-clerodanes are compact, densely functionalized diterpenes based on a stereocentre-rich decalin scaffold. To date only a few examples of the 19-nor-clerodanes have been synthesized, hence new flexible strategies are required. We herein describe the stereocontrolled construction of the cis-hydroxy decalin core in a concise fashion.
Total synthesis of capsanthin and capsorubin using Lewis acid-promoted regio- and stereoselective rearrangement of tetrasubsutituted epoxides
作者:Yumiko Yamano、Masayoshi Ito
DOI:10.1039/b710386g
日期:——
The synthesis of capsanthin 1 and capsorubin 2 was accomplished via the C(15)-cyclopentyl ketone 6 prepared by Lewis acid-promoted regio- and stereoselectiverearrangement of the epoxy dienal 5.
Synthesis of all-E- and 9Z-Heteroaryl-retinoic Acid Applying Palladium Catalyzed Coupling Reaction of (Arylvinyl)tributyl Stannane with Vinyl Triflate
作者:Akimori Wada、Govindarajuru Babu、Sayaka Shimomoto、Masayoshi Ito
DOI:10.1055/s-2001-18104
日期:——
Palladium catalyzed cross coupling reactions of (arylvinyl)tributyl stannanes with vinyl triflates resulted in the production of stereochemically pure trisubstituted E- and Z-olefins in very good yields. These olefins were transformed to the corresponding all-E- and 9Z-heteroaryl-retinoic acid analogs via Horner-Emmons reaction and subsequent basic hydrolysis in excellent yields.