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Please login to access the full content or check if you have access via Variation 4: From Alkynes and Arylhydrazines

DOI: 10.1055/sos-SD-110-00001

Joule, J. A.Science of Synthesis Knowledge Updates, (2010237.

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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M8 M8 Meeee (%) Mee
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M MM8Me 88 [‌888‌]
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M eMe 88 [‌888‌]

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