Chelation-aided generation of ketone α,β-dianions and their use as copper ate complexes. unprecedented enolate intervention in the conjugate addition to enones Ryu, I., Nakahira, H., Ikebe, M., Sonoda, N., Yamato, S., Komatsu, M. J. Am. Chem. Soc., 2000, 122, 6 pp. 1219 - 1220 DOI: 10.1021/ja993577t
Lactone synthesis based on atom transfer carbonylation Kreimerman, S., Ryu, I., Minakata, S., Komatsu, M. Org. Lett., 2000, 2, 3 pp. 389 - 391 DOI: 10.1021/ol9913441
Five- to seven-membered lactones were prepared from ω-hydroxyalkyl iodides and CO by atom transfer carbonylation without the need for transition metal catalysts. The reaction proceeds via a hybrid radical/ionic mechanism in which the intramolecular alcoholysis of an ω-hydroxyacyl iodide, arising from atom transfer carbonylation, leads to the lactone.
Selective [2+1] aziridination of conjugated dienes with a nitridomanganese complex: a new route to alkenylaziridines Nishimura, M., Minakata, S. , Thongchant, S., Ryu, I., Komatsu, M. Tetrahedron Lett., 2000, 41, 36 pp. 7089 - 7092 DOI: 10.1016/S0040-4039(00)01219-3
Conjugated dienes were successfully aziridinated using a nitridomanganese complex as a nitrogen source. The reaction proceeded selectively and in good yield via [2+1] addition to give alkenylaziridines, with no evidence for the formation of any [4+1] addition products. The first asymmetric version of the reaction was revealed in the aziridination of diene 5 with chiral complex 1.
Conjugate addition of zincates derived from keton α,β-dianions to enones. An access to unsymmetrical 1,6-diketones Ryu, I., Ikebe, M., Sonoda, N., Yamato, S., Yamamura, G., Komatsu, M. Tetrahedron Lett., 2000, 41, 30 pp. 5689 - 5692 DOI: 10.1016/S0040-4039(00)00925-4
The conjugate addition of organozincates derived from ketone α,β-dianions to enones was examined. Good yields of unsymmetrical 1,6-diketones were obtained by this reaction. A mixed zincate consisting of the dianion and methyllithium in a 2:1 ratio gave results which were comparable to those of an unmixed dianion zincate.
Epoxidation of olefins mediated by aliphatic ketiminium salts Minakata, S., Takemiya, A., Nakamura, H., Ryu, I., Komatsu, M. Synlett, 2000, , pp. 1810 - 1812 DOI: 10.1055/s-2000-8709
Generation and cycloaddition of polymer-supported azomethine imines: traceless synthesis of pyrazole derivatives from alhpasilylnitrosoamide derivatives bound to resin Wahizuka, K., Nagai, I., Minakata, S., Ryu, I. Tetrahedron Lett., 2000, 41, 5 pp. 691 - 695 DOI: 10.1016/S0040-4039(99)02140-1
1,3-Dipolar cycloaddition of polymer-supported azomethine imines with dimethyl acetylenedicarboxylate (DMAD) gave pyrazole derivatives in good yields. The azomethine imines were generated from polymer-supported α-silylnitrosoamides by a 1,4-silatropic shift. The feature of this reaction is that no cleavage operations are required after the cycloaddition.