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Chiral Thio -Ureas

Meanwhile, chiral (thio)urea catalysts have been employed for a variety of imine addition reactions consisting of Mannich, aza-Henry, Pictet-Spengler, and hydrophosphonylation reactions. ... [Pg.332]

A screening of (R)-bis-N-tosyl-BlNAM 151 and axially chiral (thio)urea derivatives 152-162 (10mol% loading 0.36 M catalyst concentration incorporating the N-aryl(alkyl) structural motif was performed at various reaction temperatures in di-chloroform using the asymmetric FC addition of N-methylindole to trans-Ji-nitrostyrene as model reachon (product 1 Scheme 6.158). The structure of bis(3,5-bistrifluoromethyl) phenyl functionalized binaphthyl bisthiourea 158 was identified... [Pg.299]

M. Shi and Y.-L. Shi reported the synthesis and application of new bifunctional axially chiral (thio) urea-phosphine organocatalysts in the asymmetric aza-Morita-Baylis-Hillman (MBH) reaction [176, 177] of N-sulfonated imines with methyl vinyl ketone (MVK), phenyl vinyl ketone (PVK), ethyl vinyl ketone (EVK) or acrolein [316]. The design of the catalyst structure is based on axially chiral BINOL-derived phosphines [317, 318] that have already been successfully utilized as bifunctional catalysts in asymmetric aza-MBH reactions. The formal replacement of the hydrogen-bonding phenol group with a (thio)urea functionality led to catalysts 166-168 (Figure 6.51). [Pg.301]

For related chiral (thio)urea catalyst-mediated electrophilic activation of... [Pg.94]

Chiral (Thio)Urea/Amine Catalysts Systems... [Pg.167]

Brpnsted Acid/Chiral (Thio)urea Combination. 173... [Pg.161]

SCHEME 6.28 Early landmark reports describing the use of chiral (thio)urea organocatalysts. [Pg.217]

Br0nsted Acids Chiral (Thio)urea Derivatives... [Pg.315]

Asymmetric chiral (thio)urea-catalyzed sulfa-Michael reactions have been extended to thioacetic acid and nitroal-kenes (Scheme 46.33). In 2006, Wang and co-workers used Takemoto s chiral thiourea 272 in the addition reaction of thioacetic acid 271 to acyclic enones 270 with modest enan-tioselectivities ranging from 20% to 1Q%P The use of... [Pg.1419]

See other pages where Chiral Thio -Ureas is mentioned: [Pg.333]    [Pg.148]    [Pg.103]    [Pg.103]    [Pg.104]    [Pg.217]    [Pg.225]    [Pg.318]    [Pg.319]    [Pg.321]    [Pg.323]    [Pg.331]    [Pg.333]    [Pg.335]    [Pg.662]    [Pg.1366]    [Pg.1368]    [Pg.1399]    [Pg.318]    [Pg.319]   


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Important Chiral (Thio)urea Organocatalysts

Urea, 1- -2-THIO

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