180891-47-8Relevant academic research and scientific papers
Palladium-catalyzed asymmetric phosphination. Enantioselective synthesis of PAMP-BH3, ligand effects on catalysis, and direct observation of the stereochemistry of transmetalation and reductive elimination
Moncarz, Julian R.,Brunker, Tim J.,Jewett, John C.,Orchowski, Michael,Glueck, David S.,Sommer, Roger D.,Lam, Kin-Chung,Incarvito, Christopher D.,Concolino, Thomas E.,Ceccarelli, Christopher,Zakharov, Lev N.,Rheingold, Arnold L.
, p. 3205 - 3221 (2008/10/08)
The complexes Pd(diphos)(o-An)(I) (o-An = o-MeOC6H4; diphos = dppe (3), (S,S)-Chiraphos (4), (R,R)-Me-Duphos (5), (R,S) -t-Bu-Josiphos (6), (R)-Tol-Binap (7)) were prepared. Complex 6 catalyzed the coupling of PH(Me)(Ph)(BH3) (2) with o-AnI in the presence of base to yield PAMP-BH3 (P(Me)(Ph)(o-An)(BH3) (1)) in low enantiomeric excess. The course of stoichiometric reactions of 3-7 with 2 and 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 were determined by X-ray crystallography after separation. The analogous Pd((R,R)-Me-Duphos)(o-An)(P(Me)(Ph)(BH3)) diastereomers (12a,b) were also separated and isolated. Treatment of 4 with highly enantioenriched 2 (R or S) gave 11a or 11b in high diastereomeric excess with retention of configuration at phosphorus. P-C reductive elimination from either isomer of highly diastereoenriched 11 in the presence of excess diphenylacetylene yielded Pd((S,S)-Chiraphos)(PhC≡CPh) (14) and highly enantioenriched PAMP-BH3 (1), with retention of configuration.
New methods for the synthesis of ArPdL2I (L = tertiary phosphine) complexes
Wallow, Thomas I.,Goodson, Felix E.,Novak, Bruce M.
, p. 3708 - 3716 (2008/10/08)
Organopalladium ArPdL2I (L = tertiary phosphine) complexes (1) can be synthesized in one step from the precursors Pd2(dba)3·C6H6 (2) (dba = t,t-dibenzylideneacetone) and (η3-allyl)PdCp (3) (Cp = η5-cyclopentadienide). Two advantages over previous synthetic methods are that this route requires only stoichiometric amounts of phosphine and that the desired complexes are easily isolated from reaction byproducts. The scope and generality of these reactions are investigated, and the synthesis of a number of new organic- and water-soluble complexes utilizing this methodology is discussed. Improved syntheses of water-soluble ligands P(C6H5)2(4-SO3KC6H 4) (5) and As(C6H5)2(4-SO3KC6H 4) (6) are presented as well.
