Okamoto, Kazuya; Sakagami, Masahiro; Feng, Fei; Togame, Hiroko; Takemoto, Hiroshi; Ichikawa, Satoshi; Matsuda, Akira Organic Letters, 2011, vol. 13, # 19 p. 5240 - 5243 doi: 10.1021/ol202124b