Halocyclization of 2-alkynylthioanisoles by cupric halides: synthesis of 2-substituted 3-halobenzo[b]thiophenes
摘要:
Reaction of 2-alkynylthioanisoles 3 with 2 equiv of CuX2 (X=Br or Cl) in refluxing CH3CN for 2.5 h gave the 2-substituted 3-halobenzo[b]thiophenes 4 in good yields. (c) 2006 Elsevier Ltd. All rights reserved.
first example of near-room-temperature α-arylation of benzo[b]thiophenes is reported. The discovery rests on the observation of a switch in α-/β-regioselectivity at different loadings of Pd2(dba)3·CHCl3 in the coupling between benzo[b]thiophene and 4-iodotoluene. We show that this unprecedented regioselectivity switch is driven by a Ag(I)-mediated C–H activation at the α-C–H position, which becomes the
Halocyclization of 2-alkynylthioanisoles by cupric halides: synthesis of 2-substituted 3-halobenzo[b]thiophenes
作者:Wen-Der Lu、Ming-Jung Wu
DOI:10.1016/j.tet.2006.10.068
日期:2007.1
Reaction of 2-alkynylthioanisoles 3 with 2 equiv of CuX2 (X=Br or Cl) in refluxing CH3CN for 2.5 h gave the 2-substituted 3-halobenzo[b]thiophenes 4 in good yields. (c) 2006 Elsevier Ltd. All rights reserved.