Asymmetric Ni(II)/Cr(II)-mediated coupling reaction: stoichiometric process.
[reaction: see text] Via an X-ray analysis, the sulfonamide bearing R(1) = i-Pr, R(2) = Me, and R(3) = Me is shown to be a tridentate ligand to a Cr(III) salt. This class of ligands, represented by R(1) = t-Bu, R(2) = 2-naphthyl, and R(3) = Me, is effective to achieve an asymmetric Ni/Cr-mediated coupling reaction and, with the C14-C38 segment of halichondrins, its synthetic potential has been demonstrated. A possible mechanism is suggested for the process.
Wan
Zhao-Kui
ZK
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Choi
Hyeong-Wook
HW
Kang
Fu-An
FA
Nakajima
Katsumasa
K
Demeke
Damtew
D
Kishi
Yoshito
Y
D002384:Catalysis; D002857:Chromium / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry*; D008024:Ligands; D018942:Macrolides; D008968:Molecular Conformation; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D013237:Stereoisomerism; D000095662:Polyether Polyketides
D002857:Chromium; D004988:Ethers, Cyclic; D008024:Ligands; D018942:Macrolides; D009532:Nickel; C070519:halichondrin B; D000095662:Polyether Polyketides