<i>Anti</i>-Carboalumination of Alkynes Using Aluminum Trihalide and Silyl Ketene Imines: Stereo- and Regioselective Synthesis of Alkenylaluminum Compounds Bearing a Cyano Group

Nishimoto, Yoshihiro; Hirase, Rina; Yasuda, Makoto

doi:10.1021/acs.orglett.8b01371

Cited by 10 publications

(2 citation statements)

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“…Recently, we reported regioselective anti -carbometalations of alkynes using organosilicon nucleophiles and metal halides such as InBr 3 [ 40 ], GaBr 3 [ 41 ], BiBr 3 [ 42 ], ZnBr 2 [ 43 ], and AlBr 3 [ 44 ]. In our established carbometalations, a metal halide directly activates an alkyne, and then an organosilicon nucleophile adds to the alkyne from an opposite site of the metal halide.…”

Section: Resultsmentioning

confidence: 99%

Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes

Nishimoto

Takata

et al. 2018

Molecules

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Regioselective anti-allylindation of alkynes was achieved using InBr3 and allylic silanes. Various types of alkynes and allylic silanes were applicable to the present allylindation. This sequential process used the generated 1,4-dienylindiums to establish novel synthetic methods for skipped dienes. The 1,4-dienylindiums were characterized by spectral analysis and treated with I2 to stereoselectively give 1-iodo-1,4-dienes. The Pd-catalyzed cross coupling of 1,4-dienylindium with iodobenzene successfully proceeded in a one-pot manner to afford the corresponding 1-aryl-1,4-diene.

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Section: Resultsmentioning

confidence: 99%

Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes

Nishimoto

Takata

et al. 2018

Molecules

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“…Alkenylaluminum 245 with an allyl cyano group readily reacted with electrophilic azodicarboxylic esters, leading to useful N ‐alkenylhydrazides 246 (Scheme 65). [103] Theoretical calculations indicated that the transformation starts with activation of alkynes at the terminal carbon by aluminum, followed by the anti ‐attack of nucleophilic silyl ketene imines 244 to generate 245 regio‐ and stereoselectively. Intermediate 245 smoothly adds to azodicarboxylate ester to furnish ( E )‐ N ‐alkenylhydrazide 246 .…”

Section: Synthesis Of N‐alkenylhydrazidesmentioning

confidence: 99%

Synthesis of N‐Aryl‐ and N‐Alkenylhydrazides through C(sp²)−N Bond Construction

Lei

Xie

et al. 2021

Eur J Org Chem

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N‐Aryl‐ and N‐alkenylhydrazides, which include a C(sp2)‐N−N motif, have attracted considerable attention not only in biologically active molecules but also because of their extensive technical applications in organic synthesis. C(sp2)−N bond construction protocols using an N‐acylhydrazine or azocarboxylic ester as the hydrazide source provide a powerful route to these compounds. These protocols exhibit different selectivity manner for the C(sp2) moiety and the regioselectivity issue of the N−N bond. This Minireview documents the available methods that have been developed based on different starting materials. The features and drawbacks of each subdivisional methodology are demonstrated.

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Synthesis of (Z)‐β‐(Carbonylamino)alkenylindium through Regioselective anti‐Carboindation of Ynamides and Its Transformation to Multisubstituted Enamides

Kang

Sakamoto

Nishimoto

et al. 2020

Chemistry A European J

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The regioselective anti-carboindation of ynamides by usingI nBr 3 and silylated nucleophilesw as developed to synthesize (Z)-b-(carbonylamino)alkenylindiums. The X-ray crystallographic analysis of an alkenylindium suggested that the reaction proceeded in an anti-addition fashion.I nc ontrastt or eported syn-carbometalationso f ynamides by using organometallics, ac ooperation of InBr 3 and silylated nucleophiles to ynamides achieveda nantiaddition, whichw as supportedb yD FT calculations. The scope of substrates included variousy namides and silylated nucleophiles, such as silyl ketenea cetals and silyl ketene imines. The transformation of synthesized alkenylindiumsb yi odination,r adicalc oupling, and Pd-catalyzed cross-couplings uccessfully afforded trisubstituted enamines with high regio-and stereoselectivities.Enamides are versatile buildingb locks for valuable nitrogencontaining compounds. [1] Ac ombinationo fc arbometalations of ynamides and transformations of the formed metalated enamides is one of the most reliable synthetic methods for multisubstituted enamides. [2] In this strategy,e stablishmento fr egioand stereoselective carbometalation is necessary for selectively synthesizing ad esired enamide among possiblei somers. Syncarbometalation of ynamides of organometallic compounds has been widely studied (Scheme1a). For example, a-(carbonylamino)alkenylmetals are obtained through the syn-addition of organocoppers, -zincs,a nd -lithiums to ynamides. [3,4] In contrast, b-(carbonylamino)alkenylmetalsa re obtained by syn-carbopalladation of ynamides by using organopalladiums. [5] How-ever, anti-carbometalation of ynamides remains underdeveloped,a lthough the intramolecular carbometalations of ynamidesh ave been reported (Scheme 1b). [6] We recently reported intermolecular anti-carbometalations of carbon-carbon triple bonds by using silylatedn ucleophiles and metal salts, such as InBr 3 ,G aBr 3 ,A lBr 3 ,B iBr 3 ,a nd ZnBr 2 . [7] Therefore, we assumedo ur strategy could achieve anti-carbometalation of ynamides. Here, we report the anti-carbometalation of ynamides by using InBr 3 and silyl ketene acetals to synthesize (Z)-b-(carbonylamino)alkenylindiums(Scheme 1c).First, we surveyed metal halides fort he carbometalation of N-ethynylpyrrolidone (1a)b yu sing the silyl ketene acetal 2a (Table 1). The reactiono fy namide 1a by using InBr 3 and 2a followed by the addition of MeOH exclusively gave the product 3aa in 96 %y ield, where the carbon-carbon bond was formed at the carbon atom adjacent to the nitrogen atom (Table 1, entry 1). This results howed that enamide 3aa was produced by the protonationo fb-(carbonylamino)alkenylindium (detailsa re described below). Notably,r egioisomers obtainedf rom a-(carbonylamino)alkenylindiumsw ere not found despite the existenceo fa na mide moiety,w hich often serves Scheme1.Carbometalation of ynamides. Entry YnamideProduct [b] Entry YnamideP roduct [b] 1 4 2 5 3 6[a] InBr 3 (0.5 mmol), 1 (0.5 mmol), 2a (1.5 mmol), CH 2 Cl 2 (1 mL), I 2 (1.5 mmol), and DMF (1.5 mL).[b] Y...

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Anti-Carboalumination of Alkynes Using Aluminum Trihalide and Silyl Ketene Imines: Stereo- and Regioselective Synthesis of Alkenylaluminum Compounds Bearing a Cyano Group

Cited by 10 publications

References 41 publications

Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes

Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes

Synthesis of N‐Aryl‐ and N‐Alkenylhydrazides through C(sp²)−N Bond Construction

Synthesis of (Z)‐β‐(Carbonylamino)alkenylindium through Regioselective anti‐Carboindation of Ynamides and Its Transformation to Multisubstituted Enamides

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Anti-Carboalumination of Alkynes Using Aluminum Trihalide and Silyl Ketene Imines: Stereo- and Regioselective Synthesis of Alkenylaluminum Compounds Bearing a Cyano Group

Cited by 10 publications

References 41 publications

Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes

Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes

Synthesis of N‐Aryl‐ and N‐Alkenylhydrazides through C(sp2)−N Bond Construction

Synthesis of (Z)‐β‐(Carbonylamino)alkenylindium through Regioselective anti‐Carboindation of Ynamides and Its Transformation to Multisubstituted Enamides

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Synthesis of N‐Aryl‐ and N‐Alkenylhydrazides through C(sp²)−N Bond Construction