Science of Synthesis

Joule, J. A., Science of Synthesis Knowledge Updates, (2010) 2, 37.

Intermolecular hydroamination of alkynes with Na-substituted arylhydrazines generates arylhydrazones. These reactions are conducted under conditions that also lead to in situ Fischer indolization. For example, a combination of titanium(IV) chloride and tert-butyl­amine (in stoichiometric proportions for the preparation of 1-methylindoles), brings about formation of indoles ‌117‌ using a variety of alkynes, as illustrated by the examples in ‌Scheme 43‌.[‌175‌] Comparable hydroaminations/Fischer cyclizations using Na-substituted arylhydrazines can be achieved with the use of the catalysts (dimethylamino)bis{2-[(dimethylamino)methyl]pyrrole}titanium [Ti(NMe2)(dap)2; dap = 2-(dimethyl­aminomethyl)pyrrole] or (dimethylamine)(dimethylamino)bis[(pentafluorophenyl)sulfanyl]titanium [Ti(NMe2)(SC6F5)2(NHMe2)].[‌176‌]

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‌Meeeeeeeeee 88‌

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‌Meeeee 88‌ Meeeeee Meeeeeee eee Meeeeeeeeeeeee ee Meeeeee eeee Meeeeeeeeeeeee[‌888‌,‌888‌]

‌Meeeeeeeeee 88‌

Meeeeeeeeeee Meeeeeeee

8-Meeee-8-eeeeee-8-eeeeee-8M-eeeeee (‌888‌, M8 = Me; M8 = Me; M8 = Me); Meeeeee Meeeeeeee:[‌888‌]

8-Meeeee-8-eeeeeeeeeeeeeee (888 ee, 8.88 eeee) eee eeeee ee eeeee eeeeeeee ee e eeee ee eee-8-eeeeeeeeeee (888 ee, 8.88 eeee), MeMe8 (8.888 eM, 8.88 eeee, 88 eee%), eee e-MeMM8 (8.888 eM, 8.88 eeee) ee eeeeeee (8 eM). Mee eeeeeeeee eeeeeee eee eeeeeee eee 88 e ee 888°M. MM8Me8 (88 eM) eee 8 M ee MMe (88 eM) eeee eeeee ee eee eeee eeeeeeeeee. Mee eeeeeeeee eeeeeee eeeee eee eeeeeeeee eeee MM8Me8 (8 × 88 eM) eee eee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eee. ee MeMMM8 (88 eM) eee eeeee (88 eM). Meeeee (MeMM8) eee eeeeeeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, eeeeeee/Me8M 88:8 ee 88:8) eeee eee eeeeeee ee e eeeeee eeeee; eeeee: 888 ee (88%).

8-[8-(eeee-Meeeeeeeeeeeeeeeeee)eeeee]-8,8-eeeeeeee-8M-eeeeee (‌888‌, M8 = Me; M8 = M; e = 8); Meeeeee Meeeeeeee:[‌888‌]

Me ee Mee-eeeeeeee eeee eeeee eeeee, 8,8-ee-eeee-eeeee-8-eeeeeeeeeeee (88 eee%) eee eeeeeeeee ee eeeeeee (8 eM). Me eeee eeee eee eeeee 8-eeeeee-8-eeeeeeeeeeeeeee (8.88 eM, 8.8 eeee), 8-(eeee-eeeeeeeeeeeeeeeeeee)eeee-8-eee (8.88 eM, 8.8 eeee), eee Me(MMe8)8 (88 eee%). Mee eeeeeee eee eeeeee ee 888°M eee 88 e, eeeee eeeeeeee ee eee eeeeeeeee ee eee eeeeeeeeeeeee. Mee eeeeeeee eeee eee eeeeee eeeee eeeee eee MeMe8 (8 eeeee) eee eeeee. Mee eeeeeee eee eeeee eeeeee ee 888°M eee 88 e. Meeee eeeeeeeeee, eeeeeee ee eee eeeeeeee eeeee eeeeeee eeeeeeee, eee eeeeee eeeeeeeeeeeeee (MeMMe/eeeeee), eee eeeeeee eee eeeeeeee ee e eeeee eeeee eee; eeeee: 88%.

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