Bis(trimethylsilyl)selenide in the Selective Synthesis of β-Hydroxy, β-Mercapto, and β-Amino Diorganyl Diselenides and Selenides Through Ring Opening of Strained Heterocycles
dialkyl diselenides and selenides is described through reaction of bis(trimethylsilyl)selenide with epoxides, thiiranes, and aziridines catalyzed by tetrabutylammonium fluoride. Selective formation of a wide variety of β-hydroxy, β-mercapto, and β-amino diselenides and selenides is achieved by controlling the reaction conditions in the regioselective attack of the silylselenide onto the ring-strained
Treatment of epoxides with bis(trimethylsilyl)‐selenide under strictly controlled conditions allows to isolate β‐hydroxy selenols which evidence an unexpected stability, taking into account their known propensity to afford diselenides. Also thiiranes and aziridines lead to functionalized selenols bearing a thiol and a N‐Ts‐ or N‐Boc‐protected amino moiety on β‐position. These selenols were stable enough
Biocatalytic Thionation of Epoxides for Enantioselective Synthesis of Thiiranes
作者:Ran Ma、Xia Hua、Cheng‐Li He、Hui‐Hui Wang、Zhu‐Xiang Wang、Bao‐Dong Cui、Wen‐Yong Han、Yong‐Zheng Chen、Nan‐Wei Wan
DOI:10.1002/anie.202212589
日期:2022.12.23
A biocatalytic thionation method is presented for the enantioselective synthesis of thiiranes from epoxides by a halohydrin dehalogenase catalyzed kinetic resolution approach using thiocyanate as a sulfur donor. Various chiral thiiranes bearing aryl and alkyl substituents were synthesized in good yields and enantioselectivities by using recombinant Escherichia coli cells expressing the engineered halohydrin
The chiral ligand (1-diphenylphosphino-3-benzyloxy)propane-2-thiol 3 has been prepared both in racemic and enantiomerically enriched (92%, e.e.) form. Addition of 2 equiv. of ligand 3 to a solution of [Pd(PPh3)(4)] gave the diastereoisomeric bischelate complexes [Pd(phosphinothiolato)(2)] 4 which exhibit a cis-trans equilibrium in solution. Formation of the diastereoisomeric complexes 4 allows the determination of the enantiomeric purity of ligand 3 by P-31 NMR spectroscopy. Addition of 1 equiv. of ligand 3 to a solution of [PdCl2(PPh3)(2)] gave the enantiomenc complexes [PdCl(phosphinothiolate)(PPh3)] 5, which can be converted to the bischelate complexes 4 by addition of a second equivalent of ligand 3. This process allows the selective preparation of the two diastereoisomeric forms of complex 4. (C) 2002 Elsevier Science Ltd. All rights reserved.