Nucleophile-dependent stereodivergence in the Pd-catalyzed intramolecular cyclization of 2-(p-tolylsulfinyl)allylacetates

Henrich, Marielouise; Delgado, Antonio; Molins, Elı́es; Roig, Anna; Llebaría, Amadeu

doi:10.1016/s0040-4039(99)00701-7

Cited by 12 publications

(9 citation statements)

References 19 publications

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“…A nucleophile-dependent stereodivergence has been observed by Llebaria and co-workers in the Pd-catalyzed cyclization of differently protected 4-acetoxy-5-(p-tolylsulfinyl)-5-hexenylamines 674 (Scheme 256). 586 In the case of the sodium salt of N-Boc protected 674a, the corresponding pyrrolidine (2R,S S )-675a was preferentially formed in 80% de, while the use of trifluoroacetamide 674b led to the formation of (2S,S S )-675b with the same diastereoselectivity. However, in the case of piperidines the diastereoselectivity was very low: 50% and 10%, respectively.…”

Section: Intramolecular Nucleophilic Substitutionmentioning

confidence: 99%

Stereodivergent Catalysis

2018

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This review covers diastereo- and enantiodivergent catalyzed reactions in acyclic and cyclic systems using metal complexes or organocatalysts. Among them, nucleophilic addition to carbon-carbon and carbon-nitrogen double bonds, α-functionalization of carbonyl compounds, allylic substitutions, and ring opening of oxiranes and aziridines are considered. The diastereodivergent synthesis of alkenes from alkynes is also included. Finally, stereodivergent intramolecular and intermolecular cycloadditions and other cyclizations are also reported.

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Section: Intramolecular Nucleophilic Substitutionmentioning

confidence: 99%

Stereodivergent Catalysis

2018

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“…However,the dependence of product stereochemistry on the identity of nucleophile is relatively rare. [24,25] On the basis of this discovery,w ep ursued efforts to optimize the hydroamination reaction with the tert-butyl carbamate nucleophile (Table 4). [26] In all cases,c omplete regio-and diastereoselectivity was observed.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…However, the dependence of product stereochemistry on the identity of nucleophile is relatively rare. [24,25] …”

mentioning

confidence: 99%

Enantioselective, Stereodivergent Hydroazidation and Hydroamination of Allenes Catalyzed by Acyclic Diaminocarbene (ADC) Gold(I) Complexes

et al. 2016

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The gold-catalyzed enantioselective hydroazidation and hydroamination reactions of allenes are presented herein. ADC gold(I) catalysts derived from BINAM were critical for achieving high levels of enantioselectivity in both transformations. The sense of enantioinduction is reversed for the two different nucleophiles, allowing access to both enantiomers of the corresponding allylic amines using the same catalyst enantiomer. Graphical AbstractChiral allylic azides and amines may be obtained by enantioselective hydroazidation and hydroamination of allenes catalyzed by acyclic diaminocarbene gold(I) catalysts derived from BINAM. The sense of enantioinduction is reversed for the two different nucleophiles, allowing easy access to both enantiomers with a single catalyst enantiomer. Keywordshydroazidation; hydroamination; enantioselective; gold catalysis; acyclic diaminocarbene Allylic amines are an important functional motif in synthetic organic chemistry and they have been utilized in the synthesis of numerous biologically active compounds. [1] Closely related allylic azides are valuable precursors for allylic amines, as well as for amino acids [2] Correspondence to: F. Dean Toste, fdtoste@berkeley.edu. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript and amine-containing natural products. [3] Allylic azides have typically been prepared via substitution reactions from the corresponding allylic halides, (homo)allylic alcohols, and their derivatives. [4] More recently, Pd-catalyzed C-H activation, [5] and Au-catalyzed hydroazidation of allenes [6] have been employed.While reports of the synthesis of allylic azides are numerous, methods for asymmetric azidation are few. [7] Fewer still are enantioselective hydroazidation reactions, which have only been reported in a formal sense via conjugate addition to activated double bonds (Scheme 1). [8][9][10] In light of recent examples of transition-metal catalysed asymmetric additions of nitrogen nucleophiles to allenes [11] and the growing utility of organic azides, we sought to develop a gold(I)-catalyzed enantioselective hydroazidation of allenes. Cognizant of potential regioselectivity issues from the Winstein rearrangement [12] of the product allylic azides, we initiated our studies using aryl allene 3a. [13] Initial studies revealed that the use of ethereal solvents was critical to obtaining reproducible data. [14] With the choice of solvent established, the enantioinduction afforded by a number of chiral gold(I) catalysts was evaluated under conditions similar to those previously reported, with trifluoroacetic acid (TFA) and trimethylsilyl azide (TMSN 3 ) used for in situ generation of hydrazoic acid (Table 2). [6] Traditional chiral phosphine gold(I) catalysts failed to afford high levels of enantioinduction (entries 1,2) as did a previously reported [15] phosphoramidite catalyst (entry 3). Chiral NHC gold(I) catalysts [16] (entries 4-6) also were found to be unsatisfactory. However, the use of a BINAM-derived ADC gold...

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“…35) and allows for further functionalization (Scheme 14). 16,26 In addition, asymmetric epoxidations, 27 intramolecular asymmetric [4+2] cycloadditions 28 and other reactions [29][30][31] are taking advantage of chiral sulfoxides as chiral auxiliaries.…”

Section: N Smentioning

confidence: 99%

Chiral Auxiliaries - Principles and Recent Applications

Gnas¹,

Glorius²

2006

Synthesis

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With modern methods for asymmetric catalysis breaking ground, the use of chiral auxiliaries seems to be old-fashioned and rather inefficient. However, for many transformations, chiral auxiliaries often represent the only selective method available. In addition, high levels of selectivity and reliability are often attractive characteristics of chiral auxiliaries and allow for the efficient and rapid synthesis of desired chiral compounds. In addition, even in cases with imperfect selectivity, the use of an attached chiral auxiliary allows the enrichment of diastereoselectivity, and hence enantioselectivity after removal of the auxiliary, by many standard separation techniques. This article gives an overview on the most important classes of chiral auxiliaries, discussing the mode of action and highlighting some recent applications. It does not deal with the use of chiral catalysts, chiral reagents or achiral auxiliaries.

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Nucleophile-dependent stereodivergence in the Pd-catalyzed intramolecular cyclization of 2-(p-tolylsulfinyl)allylacetates

Cited by 12 publications

References 19 publications

Stereodivergent Catalysis

Stereodivergent Catalysis

Enantioselective, Stereodivergent Hydroazidation and Hydroamination of Allenes Catalyzed by Acyclic Diaminocarbene (ADC) Gold(I) Complexes

Chiral Auxiliaries - Principles and Recent Applications

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