TY - JOUR
T1 - C2-symmetric bisphosphinobioxazoline as a chiral ligand. Highly enantioselective palladium-catalyzed allylic substitutions and formation of P,N,N,P tetradentate palladium (II) complexes
AU - Lee, Sang Gi
AU - Lim, Chung Woo
AU - Song, Choong Eui
AU - Kim, Kwan Mook
AU - Jun, Chul Ho
PY - 1999/6/11
Y1 - 1999/6/11
N2 - The C2-symmetric bisphosphinobioxazoline [(S,S)-Phos-Biox] 4 was found to be a highly efficient chiral ligand for Pd-catalyzed enantioselective allylic substitution of rac-1,3-diphenyl-2-propenyl acetate with dimethyl malonate and afforded enantioselectivities of up to 97% ee. Moderate enantioselectivities have been observed in Pd-catalyzed desymmetrizations of cis-1,4-bis(benzoyloxy)-cyclopent-2-ene (12) with dimethyl malonate (51-78% yield, 38-58% ee) and N-benzyl-N-methylamine (87% yield, 33% ee) nucleophiles and of biscarbamate 15 of cis-1,4-dihydroxycyclopent-2-ene (90% yield, 50% ee). A 1:1 molar mixture of (S,S)-Phos-Biox 4 with Pd(CH3CN)2Cl2 and (η3-C3H5)PdCl]2 afforded the P,N,N,P-tetradentate Pd(II) complexes 19a and 19b, respectively. The structures of the complexes 19a, b were determined by X-ray analysis. The complex 19a also exhibited high enantioselectivity (86% yield, 92% ee) in allylic substitution of rac-1,3-diphenyl-2-propenyl acetate with dimethyl malonate.
AB - The C2-symmetric bisphosphinobioxazoline [(S,S)-Phos-Biox] 4 was found to be a highly efficient chiral ligand for Pd-catalyzed enantioselective allylic substitution of rac-1,3-diphenyl-2-propenyl acetate with dimethyl malonate and afforded enantioselectivities of up to 97% ee. Moderate enantioselectivities have been observed in Pd-catalyzed desymmetrizations of cis-1,4-bis(benzoyloxy)-cyclopent-2-ene (12) with dimethyl malonate (51-78% yield, 38-58% ee) and N-benzyl-N-methylamine (87% yield, 33% ee) nucleophiles and of biscarbamate 15 of cis-1,4-dihydroxycyclopent-2-ene (90% yield, 50% ee). A 1:1 molar mixture of (S,S)-Phos-Biox 4 with Pd(CH3CN)2Cl2 and (η3-C3H5)PdCl]2 afforded the P,N,N,P-tetradentate Pd(II) complexes 19a and 19b, respectively. The structures of the complexes 19a, b were determined by X-ray analysis. The complex 19a also exhibited high enantioselectivity (86% yield, 92% ee) in allylic substitution of rac-1,3-diphenyl-2-propenyl acetate with dimethyl malonate.
UR - http://www.scopus.com/inward/record.url?scp=0345120713&partnerID=8YFLogxK
U2 - 10.1021/jo990126i
DO - 10.1021/jo990126i
M3 - Article
AN - SCOPUS:0345120713
SN - 0022-3263
VL - 64
SP - 4445
EP - 4451
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 12
ER -