Table 3.

Enantioselective copper-catalyzed conjugate addition of EtMgBr to cyclic enones

Graphic

Entry*11 Ligand Regio, % ee12, % 12 Conf(R/S)
1§ 11a 1 80 [60] 87 12a (+)-R
2 11a 6 96 78 12a (-)-S
3 11b 1 69 6 12b (-)-S
4 11b 6 99 82 12b (+)-R
5 11b 7 99 92 12b (+)-R
6 11c 1 99 47 12c (+)-R
7§ 11c 6 99 [75] 79 12c (-)-S
8 11c 7 99 82 12c (-)-S
  • Conf, absolute configuration.

  • * More than 98% conversion after 2 h at -60°C using CuBr·SMe2.

  • Regioselectivity = [12/(12 + 13)] × 100.

  • Absolute configuration and sign of the optical rotation.

  • § Isolated yields are given in brackets.