NEW ENTRY TO 1,4,5,6-TETRAHYDRO-2H-INDOL-2-ONES USING A CATIONIC 5-ENDO-TRIGONAL CYCLIZATION ONTO ENAMIDES

Authors
ISHIBASHI H HIGUCHI M MASUKO H KODAMA K IKEDA M
Citation
H. Ishibashi et al., NEW ENTRY TO 1,4,5,6-TETRAHYDRO-2H-INDOL-2-ONES USING A CATIONIC 5-ENDO-TRIGONAL CYCLIZATION ONTO ENAMIDES, Heterocycles, 46, 1997, pp. 37-40
Citations number
7
Journal title
Heterocycles → ACNP
ISSN journal
03855414
Volume
46
Year of publication
1997
Pages
37 - 40
Database
ISI
SICI code
0385-5414(1997)46:<37:NET1UA>2.0.ZU;2-F
Abstract
A new method for the synthesis of 1,4,5,6-tetrahydro-2H-indol-2-ones b y means of 5-endo-trigonal cyclization of alpha-thiocarbocations gener ated from sulfoxide (12) and alpha-chlorosulfide (17) is described. Th e sulfoxide (12), upon heating with TsOH, gave 14, which eliminated be nzenethiol to give tetrahydroindolone (15). By contrast, the chlorosul fide (17), upon treatment with TiCL4 gave the desulfurized tetrahydroi ndolone (18). The mechanism for the formation of 18 is also discussed.