The stereoselective synthesis of P-chiral phosphines through the additions onto the P=C double bond of prochiral phosphaalkenes

(1)邻苄基杂原子取代芳基磷酸烯烷氧基化法非对映选择性合成磷酸钯环丙烷。邻苄基位置有配位杂原子取代的芳基磷酸烯烷氧基化可立体选择性地合成磷酸钯环丙烷配合物。发现配合物在空气中对硅胶色谱是稳定的。芳基磷烯的苯基杂原子取代基作为钯（II）配合物的配体。该反应的非对映选择性主要由苯基立体中心的杂原子取代基控制。我们发现了一种合成对映体纯P-C-S螯合配体钯配合物的新方法。(2)硫酸阴离子在三羰基铬配位芳基磷酸烯烃上的亲核加成前手性磷酸烯烃的P=C双键上的立体选择性加成是合成P手性磷酸烯烃的有效方法之一。然而，空间保护的磷烯烃在空气中是稳定的，其反应活性很低。三羰基铬配位芳基磷酸烯烃有望提高对亲核试剂的反应性，因为三羰基铬片段由于其强大的吸电子能力而稳定了苯基碳离子。虽然(E)-2-苯基-1-（2,4,6-三-丁基苯基）磷酸乙烯在THF中不与硫代酸锂反应，但相应的铬配合物得到了收率很高的硫代膦。我们发现了一种合成大体积p -手性配体的新方法。

(1) Diastereoselective Synthesis of Phosphapalladacyclopropanes by Alkoxypalladation of Arylphosphaalkenes Bearing ortho-Benzylic Heteroatom SubstituentAlkoxypalladation of the kinetically protected arylphosphaalkenes bearing a coordinative heteroatom substituent at the ortho-benzylic positeion gave the phosphapalladacyclopropane complexes stereoselectively. The complexes were found to be stable to silica gel chromatography in the air. The benzylic heteroatom substituent of arylphosphaalkenes acts as the ligand of the resulting palladium (II) complexes. The diastereoselectivity of this reaction is mainly controlled by the heteroatom substituent at the benzylic stereogenic center. We have found a novel approach for the synthesis of enantio-pure P-C-S pincer ligand coordinated palladium complexes.(2) Nucleophilic Addition of Thiolate Anion to Tricarbonylchromium-Coordinated ArylphospaalkenesThe stereoselective additions onto the P=C double bond of prochiral phosphaalkenes are one of the efficient method for the synthesis of P-chiral phosphines. However, the reactivity of sterically protected phosphaalkenes, which are stable in the air, is rather low. Tricarbonylchromium-coordinated arylphosphaalkenes are expected to increase the reactivity toward nucleophiles, because the tricarbonylchromium fragment stabilizes benzylic carbanions due to its strong electron-withdrawing ability. Although (E)-2-phenyl-1-(2,4,6-tri-t-butylphenyl)phosphaethene did not reacted with lithium thiolate in THF, the corresponding chromium complex gave thiophosphine in excellent yield. We have found a new method for the synthesis of bulky P-chiral ligands.