1,3‐bis[N‐sulfonyl‐(1R,2S)‐1,3‐diphenyl‐2‐aminopropanol]benzene: An excellent ligand for titanium‐catalyzed asymmetric AlPh3(THF) additions to aldehydes

Hsieh, Sheng-Hsiang; Chen, Chien An; Chuang, Da‐Wei; Yang, Mao‐Chih; Yang, Hsu‐Tang; Gau, Han‐Mou

doi:10.1002/chir.20572

Cited by 18 publications

(2 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In 2008 Muramatsu and Harada63 introduced a method wherein Grignard reagents (1.2 equiv) could be added to titanium tetraisopropoxide (3 equiv) in the presence of 2 mol % 3-(3,5-Ph 2 -C 6 H 3 )-H 8 -BINOL and aldehydes to provide diarylmethanols with high ee. In a similar vein, Gau and coworkers employed salt-free Ar 3 Al•THF reagents in combination with titanium tetraisopropoxide and either H 8 -BINOL64 or sulfonamide alcohol-based ligands,65 which led to diarylmethanols with high enantioselectivities. These reactions may proceed via an Ar-Ti intermediate 66…”

Section: Introductionmentioning

confidence: 99%

Practical Catalytic Asymmetric Synthesis of Diaryl-, Aryl Heteroaryl-, and Diheteroarylmethanols

2009

View full text Add to dashboard Cite

Enantioenriched diaryl-, aryl heteroaryl-and diheteroarylmethanols exhibit important biological and medicinal properties. One-pot catalytic asymmetric syntheses of these compounds beginning from readily available aryl bromides are introduced. Thus, lithium-bromide exchange with commercially available aryl bromides and n-BuLi was followed by salt metathesis with ZnCl 2 to generate ArZnCl. A second equivalent of n-BuLi was added to form the mixed organozinc, ArZnBu. In the presence of enantioenriched amino alcohol-based catalysts, ArZnBu adds to aldehydes to afford essentially racemic diarylmethanols. The low enantioselectivities were attributed to a LiCl-promoted background reaction. To inhibit this background reaction, the chelating diamine TEEDA (tetraethylethylene diamine) was introduced prior to aldehyde addition. Under these conditions, enantioenriched diarylmethanols were obtained with >90% ee. Arylations of enals generated allylic alcohols with 81-90% ee. This procedure was unsuccessful, however, when applied to heteraryl bromides, which was attributed to decomposition of the heteroaryl lithium under the salt metathesis conditions. To avoid this problem, the metathesis was conducted with EtZnCl, which enabled the salt metathesis to proceed at low temperatures. The resulting EtZn(Ar Hetero ) intermediates (Ar Hetero =2-and 3-thiophenyl, 2-benzothiophenyl, 3-furyl, and 5-indolyl) were successfully added to aldehydes and heteroaryl aldehydes with enantioselectivities between 81-99%. These are the first examples of catalytic and highly enantioselective syntheses of diheteroarylmethanols. In a similar fashion, ferrocenyl bromide was used to generate FcZnEt and the ferrocenyl group added to benzaldehyde and heteroaromatic aldehydes to form ferrocene-based ligand precursors in 86-95% yield with 96-98% ee. It was also found that the arylation and heteroarylation of enals could be followed by diastereoselective epoxidations to provide epoxy alcohols with high enantio-and diastereoselectivities in a one-pot procedure.

show abstract

Section: Introductionmentioning

confidence: 99%

Practical Catalytic Asymmetric Synthesis of Diaryl-, Aryl Heteroaryl-, and Diheteroarylmethanols

2009

View full text Add to dashboard Cite

show abstract

“…However, organoaluminum reagents were used in limited cases of asymmetric catalytic alkylation, allylation, allylic alkylation, and alkynylation reactions, achieving products in good to excellent enantioselectivies. Recently, our group demonstrated that the [AlAr 3 (THF)] reagents are efficient aryl nucleophiles for the additions to aldehydes and ketones catalyzed by titanium catalyst of ( R )-H 8 -BINOL, ( S )-BINOL (BINOL = 2,2′-dihydroxy-1,1′-binaphthyl), or sulfonamide alcohols. Furthermore, [AlAr 3 (THF)] is an effective coupling reagent with aryl halides .…”

mentioning

confidence: 99%

Highly Enantioselective Vinyl Additions of Vinylaluminum to Ketones Catalyzed by a Titanium(IV) Catalyst of (S)-BINOL

Biradar

Gau

2008

Org. Lett.

View full text Add to dashboard Cite

We report a novel asymmetric addition of vinyl group to ketones using vinylaluminum reagents catalyzed by in situ prepared Ti(O(i)Pr)(4) complexes of (S)-BINOL to afford diversified tertiary allylic alochols. Varieties of aromatic ketones bearing either an electron-donating or an electron-withdrawing substituent on the aromatic ring were examined to afford products in excellent enantioselectivities of up to 98% ee with high yields. A 10-fold scale-up reaction afforded the product in a similar yield with a comparable enantioselectivity. More importantly, additions of a variety of vinyl reagents including functionalized vinyls were demonstrated, affording tertiary allylic alcohols with good to excellent enantioselectivities of up to 96% ee.

show abstract

Chiral Lithium Amido Aryl Zincates: Simple and Efficient Chemo‐ and Enantio‐Selective Aryl Transfer Reagents

et al. 2019

View full text Add to dashboard Cite

An enantioselective aryl transfer is promoted using chiral tricoordinated lithium amido aryl zincates that are easily accessible reagents and whose chiral appendage is simply recovered for reuse. The arylation reaction is run in good yields (60 % average on twenty substrates) and high enantiomeric excesses (95 % ee average). This occurs whatever the ortho, meta, or para substituent borne by the substrate and a complete chemoselectivity is observed with respect to the aldehyde function. Sensitive groups such as nitriles, esters, ketones, and enolisable substrates resist to the action of the ate reagent, warranting a large scope to this methodology.

show abstract

1,3‐bis[N‐sulfonyl‐(1R,2S)‐1,3‐diphenyl‐2‐aminopropanol]benzene: An excellent ligand for titanium‐catalyzed asymmetric AlPh₃(THF) additions to aldehydes

Cited by 18 publications

References 61 publications

Practical Catalytic Asymmetric Synthesis of Diaryl-, Aryl Heteroaryl-, and Diheteroarylmethanols

Practical Catalytic Asymmetric Synthesis of Diaryl-, Aryl Heteroaryl-, and Diheteroarylmethanols

Highly Enantioselective Vinyl Additions of Vinylaluminum to Ketones Catalyzed by a Titanium(IV) Catalyst of (S)-BINOL

Chiral Lithium Amido Aryl Zincates: Simple and Efficient Chemo‐ and Enantio‐Selective Aryl Transfer Reagents

Contact Info

Product

Resources

About