Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 8 de 8
Filter
Add more filters










Database
Language
Publication year range
1.
J Org Chem ; 84(12): 7543-7563, 2019 Jun 21.
Article in English | MEDLINE | ID: mdl-30830782

ABSTRACT

Effective desymmetrization in copper-catalyzed intramolecular C-H insertion reactions of α-diazo-ß-oxosulfones in the formation of fused thiopyran dioxides is described for the first time. The use of a copper-bis(oxazoline)-NaBARF catalyst complex system leads to formation of the major thiopyran dioxide stereoisomer with up to 98:2 dr and up to 98% ee. The effect of varying the bis(oxazoline) ligand, copper salt, and site of C-H insertion on both diastereo- and enantioselectivities of these intramolecular C-H insertion reactions has been investigated. Similarly, desymmetrization in the formation of a fused cyclopentanone proceeds with up to 64% ee. These results represent the highest enantioselectivity reported to date in a copper-mediated desymmetrization through C-H insertion.

2.
Org Biomol Chem ; 17(5): 1284-1285, 2019 01 31.
Article in English | MEDLINE | ID: mdl-30652717

ABSTRACT

Correction for 'Enantioselective copper catalysed intramolecular C-H insertion reactions of α-diazo-ß-keto sulfones, α-diazo-ß-keto phosphine oxides and 2-diazo-1,3-diketones; the influence of the carbene substituent' by Amy E. Shiely et al., Org. Biomol. Chem., 2017, 15, 2609-2628.

3.
Org Biomol Chem ; 15(12): 2609-2628, 2017 Mar 22.
Article in English | MEDLINE | ID: mdl-28267185

ABSTRACT

Enantioselectivities in C-H insertion reactions, employing the copper-bis(oxazoline)-NaBARF catalyst system, leading to cyclopentanones are highest with sulfonyl substituents on the carbene carbon, and furthermore, the impact is enhanced by increased steric demand on the sulfonyl substituent (up to 91%ee). Enantioselective intramolecular C-H insertion reactions of α-diazo-ß-keto phosphine oxides and 2-diazo-1,3-diketones are reported for the first time.

4.
Org Lett ; 18(19): 4978-4981, 2016 10 07.
Article in English | MEDLINE | ID: mdl-27656907

ABSTRACT

Enantio- and diastereoselective hydrogenation of ß-keto-γ-lactams with a ruthenium-BINAP catalyst, involving dynamic kinetic resolution, has been employed to provide a general, asymmetric approach to ß-hydroxy-γ-lactams, a structural motif common to several bioactive compounds. Full conversion to the desired ß-hydroxy-γ-lactams was achieved with high diastereoselectivity (up to >98% de) by addition of catalytic HCl and LiCl, while ß-branching of the ketone substituent demonstrated a pronounced effect on the modest to excellent enantioselectivity (up to 97% ee) obtained.

6.
J Org Chem ; 79(8): 3688-95, 2014 Apr 18.
Article in English | MEDLINE | ID: mdl-24641629

ABSTRACT

The novel preparation of 2-aminopyridoimidazoles and 2-aminobenzimidazoles via the cyclization of (2-aminopyridin-3-yl)urea and (2-aminophenyl)urea substrates in the presence of phosphorus oxychloride is described. This methodology is demonstrated for a range of urea substrates with aminoimidazole products obtained in good yields and with excellent levels of purity.


Subject(s)
Aminopyridines/chemical synthesis , Benzimidazoles/chemical synthesis , Imidazoles/chemical synthesis , Urea/analogs & derivatives , Aminopyridines/chemistry , Catalysis , Cyclization , Imidazoles/chemistry , Molecular Structure , Urea/chemical synthesis , Urea/chemistry
7.
J Org Chem ; 78(12): 5955-63, 2013 Jun 21.
Article in English | MEDLINE | ID: mdl-23718859

ABSTRACT

An efficient synthetic approach leading to introduction of the hydroxymethyl group to an aryl moiety via combination of the Bouveault formylation and hydride reduction has been optimized using a rational, mechanistic-based approach. This approach enabled telescoping of the two steps into a single efficient process, readily amenable to scaleup.


Subject(s)
Aldehydes/chemical synthesis , Morpholines/chemical synthesis , Phenylethyl Alcohol/chemical synthesis , Antidepressive Agents/chemistry , Humans , Molecular Structure , Morpholines/chemistry , Phenylethyl Alcohol/analogs & derivatives , Phenylethyl Alcohol/chemistry , Stereoisomerism
8.
Org Biomol Chem ; 9(3): 667-9, 2011 Feb 07.
Article in English | MEDLINE | ID: mdl-21120229

ABSTRACT

Asymmetric copper-catalysed intramolecular C-H insertion reactions of a series of α-diazo-ß-keto sulfones are reported. Enantioselectivities of up to 82% ee were achieved in moderate to good yield. These results represent the highest level of enantiocontrol achieved to date for a copper-catalysed cyclopentanone synthesis via C-H insertion.


Subject(s)
Azo Compounds/chemistry , Carbon/chemistry , Copper/chemistry , Hydrogen/chemistry , Sulfones/chemistry , Catalysis , Ligands , Molecular Structure , Stereoisomerism
SELECTION OF CITATIONS
SEARCH DETAIL
...