Lee, Hyeon Kyu; Chun, Jong Soo; Pak, Chwang SiekLee, Hyeon Kyu; Chun, Jong Soo; Pak, Chwang Siek Tetrahedron LettersTetrahedron, 20012003, vol. 4259, # 2034 p. 3483 - 34866445 - 6454 doi: 10.1016/S0040-4039(01)00470-110.1016/S0040-4020(03)01063-9