Tandem Reaction of Propargylic Alcohol, Sulfonamide, and N-Iodosuccinimide: Synthesis of N-(2-Iodoinden-1-yl)arenesulfonamide

Abstract

An efficient and straightforward strategy for the synthesis of N-(2-haloinden-1-yl)arenesulfonamides from propargylic alcohols and sulfonamides is described. Allenesulfonamide is postulated to be the key intermediate for this tandem transformation.

An efficient and practical entry to 2-amido-dienes and 3-amido-trienes from allenamides through stereoselective 1,3-hydrogen shifts

“…While under thermal conditions, a biradical intermediate is at play [2,4,24], under acidic conditions, the isomerization clearly proceeds through an N -acyl iminium intermediate via protonation of the allenamide (Fig. 2, center).…”

“…The major question here is how viable is it to access conjugated dienes from structurally more challenging allenes through a kinetically difficult and stereochemically undistinguished isomerization. It might not seem like a logical approach; however, our justification is that since there are few well established routes for preparing amido-dienes, our allenamide isomerization strategy (for reviews on allenamide chemistry see [21–23], for reports in 2009, 2010 and 2011 see [24–43], for earlier studies on allenamides see [44–46]) can open the door to construct synthetically useful amido-dienes (for a review on the synthesis of enamides see [47], for reviews on the chemistry of dienamides see [48–50], for reviews on the chemistry of 2-amino or 2-amido-dienes see [51–52]). Problems with the two primary approaches to access amido-dienes [47] are that acid-mediated condensations suffer from functional group tolerances, and metal-mediated coupling methods (for reviews on Cu-mediated C–N and C–O bond formations see [53–55], for some examples see [56–58]) suffer from limited access as well as the instability of halo-dienes (Scheme 2).…”

Substituent‐Dependent, Iron‐Mediated Tandem Cyclization of Diynes with Benzaldehyde Acetals to Form Highly Functionalized Indene Derivatives

“…[1] Diynes have been used as versatile building blocks for the preparation of carbo-and heterocycles through transition-metal catalyzed carbocyclization, cycloaddition, and cycloisomerization reactions. [7] Although enediynes have been documented for the synthesis of indenes, [8] diynes have seldom been applied for this purpose. [7] Although enediynes have been documented for the synthesis of indenes, [8] diynes have seldom been applied for this purpose.…”

Synthesis of dihydrobenzofurans and dihydroindoles by intramolecular Friedel-Crafts reaction of aryloxy- and arylamino-substituted propargylic alcohols

“…The allenes generated in situ could then undergo various cascade reactions to form many useful structural frameworks. [20][21][22][23][24][25][26] In a recent report, the Zhou group have developed an intramolecular Friedel-Crafts (IFC) reaction that provides a facile and versatile method for one-step construction Very recently, our group has reported the application of propargylic alcohols for the construction of substituted fluorenes, in which five-membered rings were constructed by IFC reactions. 29 It was envisaged that the similar IFC reaction of propargylic alcohols may also be applied to construct a five-membered heterocyclic skeleton.…”