| Number | Date | Country | Kind |
|---|---|---|---|
| 61-304810 | Dec 1986 | JPX | |
| 62-52625 | Mar 1987 | JPX |
| Entry |
|---|
| Fujita et al, Tetrahedron Letters, vol. 27, pp. 2139 to 2141 (1986). |
| Rabjohn et al, "Organic Syntheses", Collective vol. 4, pp. 268 to 270 (1963). |
| Schwarz et al, Chemical Abstracts, vol. 101, #130888k (1984). |