Zhang, Yanying; Tu, Song; Mitsudo, Koichi; Tanaka, Hideo; Suematsu, Shunzo; Machida, Kenji; Horii, Daisuke; Ishimoto, Shuichi; Tamamitsu, Kenji Tetrahedron Letters, 2009 , vol. 50, # 44 p. 6057 - 6059