Palladium-Catalyzed Asymmetric Phosphination. Enantioselective Synthesis of PAMP−BH<sub>3</sub>, Ligand Effects on Catalysis, and Direct Observation of the Stereochemistry of Transmetalation and Reductive Elimination
作者:Jillian R. Moncarz、Tim J. Brunker、John C. Jewett、Michael Orchowski、David S. Glueck、Roger D. Sommer、Kin-Chung Lam、Christopher D. Incarvito、Thomas E. Concolino、Christopher Ceccarelli、Lev N. Zakharov、Arnold L. Rheingold
DOI:10.1021/om030144x
日期:2003.8.1
NaOSiMe3 depended on the diphosphine ligand. Complexes 6 and 7 gave PAMP−BH3 (1) and Pd(0) species; no intermediates were observed. With 3, the intermediate Pd(dppe)(o-An)(P(Me)(Ph)(BH3)) (10) was observed by 31P NMR, while 4 gave the isolable diastereomeric palladium complexes (SP)-Pd((S,S)-Chiraphos)(o-An)(P(Me)(Ph)(BH3)) (11a) and (RP)-Pd((S,S)-Chiraphos)(o-An)(P(Me)(Ph)(BH3)) (11b), whose absolute configurations
配合物Pd(diphos)(o -An)(I)(o -An = o -MeOC 6 H 4 ; diphos = dppe(3),(S,S)-Chiraphos(4),(R,R)-制备了Me-Duphos(5),(R,S)-t -Bu-Josiphos(6),(R)-Tol-Binap(7))。配合物6催化PH(Me)(Ph)(BH 3)(2)与o的偶联-AnI在碱的存在下以低对映体过量产生PAMP-BH 3(P(Me)(Ph)(o -An)(BH 3)(1))。的化学计量的反应过程3 - 7与2和NaOSiMe 3依赖于二膦配体。配合物6和7产生PAMP-BH 3(1)和Pd(0)物种;没有观察到中间体。在3中,通过31 P NMR观察到中间体Pd(dppe)(o -An)(P(Me)(Ph)(BH 3))(10),而4给出了可分离的非对映体钯配合物(S P)-Pd((S,S)-Chiraphos)(o