Shimada, Kazuaki; Gong, Yaling; Nakamura, Hidenori; Matsumoto, Rei; Aoyagi, Shigenobu; Takikawa, Yuji Tetrahedron Letters, 2005, vol. 46, # 21 p. 3775 - 3778 doi: 10.1016/j.tetlet.2005.03.153