Cationic [2,6-Bis(2‘-oxazolinyl)phenyl]palladium(II) Complexes: Catalysts for the Asymmetric Michael Reaction
作者:Mark A. Stark、Geraint Jones、Christopher J. Richards
DOI:10.1021/om990710h
日期:2000.4.1
Treatment of the palladium complexes with AgBF4, AgOTf, or AgSbF6 in wet CH2Cl2 provided a series of cationic [2,6-bis(2‘-oxazolinyl)phenyl]palladium complexes (28−87%) containing water coordinated to palladium, as established by an X-ray crystal structure analysis of (S,S)-[2,6-bis(4‘-isopropyl-2‘-oxazolinyl)phenyl]aquopalladium(II) trifluoromethanesulfonate. All of the cationic complexes proved to be
1,3-二氰基苯与β-氨基醇(S)-H 2 NCHRCH 2 OH(R = i Pr,i Bu,t Bu,CH 2 Cy,CH 2 Ph)和(R)-H 2 NCHPhCH 2反应OH产生了新的1,3-双(2'-恶唑啉基)苯(30-51%)。将它们与1,3-双(4',4'-二甲基-2'-恶唑啉基)苯一起用LDA / TMEDA处理,然后添加PdBr 2(1,5-COD),得到[2, 6-双(2'-恶唑啉基)苯基]溴化钯(II)络合物(21-41%)。在两种情况下均未获得配合物(R = Ph,CH 2Ph)是由于LDA / TMEDA导致的恶唑啉开环。在潮湿的CH 2 Cl 2中用AgBF 4,AgOTf或AgSbF 6处理钯配合物可得到一系列阳离子的[2,6-双(2'-恶唑啉基)苯基]钯配合物(28-87%),其水配位后通过对(S,S)-[2,6-双(4'-异丙基-2'-恶唑啉基)苯基]