Regioselective Cyclization of 1-Trimethylacetylindole Derivatives at the 4-P0siti0n of Indole Nucleus

Abstract

1-Trimethylacetyl derivatives 9 and 10 of 3-(2-butenyl)indole 7 and 3-(3-methyl-2-butenyl)indole 8 were regioselectively cyclized at the 4-position of indole nucleus.In the biosynthesis of ergot alkaloids 3, a prenyl group is first introduced at 4-position of tryptophan as shown in the scheme(l).Although many attempts to introduce a such substituent at the position of indole nucleus have been studied for a long time, no successful method has been reported except a few cases(2,3).

Oligomerization ofN-Tosylindole with Aluminum Chloride

“…We have developed novel methods [2][3][4][5][6][7][8][9][10] for introducing various functional groups on the benzene part of such stabilized indoles as N-pivaloylindole and applied these to the total synthesis of teleocidin B 11) and to an efficient synthesis of the mitomycin skeleton. [12][13][14] In a study of the chemical reactivity of N-pivaloylindole, we found novel dimerization of N-pivaloylindole in the presence of AlCl 3 to give 1a-c. 15) These compounds were completely different from oligomerization products 2 and 3 [16][17][18][19] of indole itself under acidic conditions.…”