1988 Fiscal Year Final Research Report Summary
Regiocontrol of ring cleavage and cycloaddition of oxiranes catalyzed by organotin- and organoantimony halides
| Project/Area Number |
62550613
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
有機工業化学
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| Research Institution | Osaka University |
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Principal Investigator |
BABA Akio Osaka University, Faculty of Engineering Associate Professor, 工学部, 助教授 (20144438)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Ketene / amine / isocyanate / carbodiimide / oxirane / regiocontrol / organotin halide / organoanimony halide / cycloaddition |
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| Research Abstract |
Oxiranes are industrially available and useful reagents, but too unstable to treat under acidic or basic conditions. Complete regiocontrol of the oxirane-ring cleavage, so, is a significant and serious problem in modern chemistry. In this study, following results were obtained on this subject.
1. Cycloaddition of monosubstituted oxiranes with heterocumulenes.
In the presence of organotin halide-base complex, the reactions with isocyanates, carbodiimides proceeded via -cleavage of oxirane to furnish the corresponding 3,5-disubstituted heterocyclic compounds under very mild conditions. On the contrary, Ph_4SbI promoted the -cleavaged reaction of oxiranes to gave isomeric heterocyclic compounds, 3,4-disubstituted ones, in high yields. The latter type of cycloaddition has not been reported so far. On the other hand, in the reaction of ketene with oxiranes SN catalyst and SB catalyst gave 1,3-dioxolane and -lactone derivatives, respectively.
Thus, compensatable use of the both catalysts would be expected to be adopted widely in organic synthesis.
2. Reaction of amines with oxiranes catalyzed by Ph_4SbOTf.
Tile reaction was effected under complete anhydrous conditions in the presence of catalytic amounts of Ph_4SbOTf. Moreover, this catalyst allowed the use of an equimolar amount of amine, although excess amounts have been indespensable in conventional systems.
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