phenylphosphine - borane;phenylphosphine-borane;phenyl-phosphine; compound with borane;(phenyl)PH2*BH3;Phenyl-phosphin; Verbindung mit Boran;Borane;phenylphosphane
Enantioselective Synthesis of P-Stereogenic Benzophospholanes via Palladium-Catalyzed Intramolecular Cyclization
作者:Tim J. Brunker、Brian J. Anderson、Natalia F. Blank、David S. Glueck、Arnold L. Rheingold
DOI:10.1021/ol0700512
日期:2007.3.1
Enantioselective or diastereoselective intramolecular cyclization of functionalized secondary phosphines or their borane adducts catalyzed by chiral Pd(diphosphine) complexes gave P-stereogenic benzophospholanes in up to 70% ee. These results provide a new method for the synthesis of chiral phospholanes, which are valuable ligands in asymmetriccatalysis. [reaction: see text]
Synthesis of 2,6-dimethyl-9-aryl-9-phosphabicyclo[3.3.1]nonanes: their application to asymmetric synthesis of chiral tetrahydroquinolines and relatives
Synthesis of 2,6-dimethyl-9-aryl-9-phosphabicyclo[3.3.1]nonanes from 1,5-cyclooctadiene and their application to asymmetric cyclization leading to chiral tetrahydroquinolines and relatives through palladium-catalyzed allylic alkylation are described. (c) 2007 Elsevier Ltd. All rights reserved.
New chiral phospholanes 6 were prepared in both enantiomeric forms starting from L- and D-tartaric acid. The key step in the synthetic sequence is the double hydrophosphination of unsaturated chiral bis(lactone) 9 by NaPhPH(BH3). This method was used for the first time in the formation of chiral phospholanes. The structure of phospholane 6a was confirmed by X-ray crystallography. sigma-Donor properties of the phospholanes were estimated by measurement of (1)J((PSe)-P-31-Se-77) coupling constants in the corresponding phosphine selenides. The new phospholanes were tested as ligands in the Rh-catalyzed enantioselective hydrogenation of functionalized standard olefins (65-92% ee). (c) 2006 Elsevier Ltd. All rights reserved.
Hydrophosphination of α,β-unsaturated esters by primary phosphine-boranes; a useful entry to symmetrical and unsymmetrical phosphine-boranes
The reactivity of primary phosphine-boranes RPH(2) . BH3 (R = Ph and Me) towards CH2=CHCO(2)Me and CH2=CHP(O)(OMe)(2) is discussed. Hydrophosphination is the major process. The presence of the free phosphine (0-20%) in the crude media indicates that a competitive hydroboration reaction also occurs. The P-H addition was found to be controllable to give, in reasonable yields. either the mono or the bis-adducts. All the adducts are stable and are fully characterized, The preparation of an unsymmetrical bis-adduct is also presented. (C) 1997 Published by Elsevier Science Ltd.