A Convenient (E)-Stereoselective Synthesis of Alkenylphosphonates
摘要:
Diethyl (E)-alkenylphosphonates have been prepared stereoselectively by dehydration of the corresponding beta-hydroxyphosphonates using DCC/CuCl2 in refluxing toluene. Starting beta-hydroxyphosphonates were obtained in high yield from diethyl methylphosphonate.
A Convenient (E)-Stereoselective Synthesis of Alkenylphosphonates
摘要:
Diethyl (E)-alkenylphosphonates have been prepared stereoselectively by dehydration of the corresponding beta-hydroxyphosphonates using DCC/CuCl2 in refluxing toluene. Starting beta-hydroxyphosphonates were obtained in high yield from diethyl methylphosphonate.
A novel aerobic manganese-catalyzed oxophosphorylation reaction of carbon-carbon doublebonds of styrene derivatives and vinyl ethers using diethyl H-phosphonates was developed. This direct transformation of alkenes to β-ketophosphonate readily proceeded at room temperature via the direct incorporation of molecular oxygen present in air (open flask).
essential building blocks for organophosphorus compounds. However, the asymmetric synthesis of these units remains a significant challenge. Herein, we describe a one-pot chemoenzymatic cascade process to access chiral β-hydroxyphosphonates, which combines photo-oxidative chemical reactions and bioreductions. The incorporation of photooxidation in the chemical reaction resulted in up to 92% yield and
手性 β-羟基膦酸酯是有机磷化合物的重要组成部分。然而,这些单元的不对称合成仍然是一个重大挑战。在这里,我们描述了一种获得手性β-羟基膦酸盐的一锅化学酶级联过程,该过程结合了光氧化化学反应和生物还原。化学反应中光氧化的结合导致级联中 β-羟基膦酸酯的产率高达 92%,对映体过量 (ee) 大于 99%。此外,( S )-(2-羟基-2-苯基乙基)膦酸二乙酯的放大也证明了该策略的潜在应用。
Kinetic resolution of 2-hydroxy-2-aryl-ethylphosphonates by a non-enzymatic acylation catalyst
作者:Laura Mesas-Sánchez、Alba E. Díaz-Álvarez、Petr Koukal、Peter Dinér
DOI:10.1016/j.tet.2014.03.102
日期:2014.6
Optically pure hydroxyphosphonates are widely used as derivatizable compounds that can be incorporated into a variety of synthetic strategies for the preparation of other high value organic products. A non-enzymatic kinetic resolution procedure to obtain chiral 2-hydroxy-2-arylethylphosphonates from the easily available racemic counterparts is described. A range of 2-hydroxy-2-arylethylphosphonates was efficiently resolved employing a planar-chiral DMAP derived catalyst with good selectivities (up to S=68). The chiral hydroxyphosphonates were isolated in good yields and high enantiomeric excess (>94% ee). (C) 2014 Elsevier Ltd. All rights reserved.