Torii, Sigeru; Hase, Tomoyuki; Kuroboshi, Manabu; Amatore, Christian; Jutand, Anny; Kawafuchi, Hiroyuki Tetrahedron Letters, 1997, vol. 38, # 42 p. 7391 - 7394 doi: 10.1016/S0040-4039(97)01732-2