Enhancement of stereoselectivity in catalytic cyclopropanation reactions

Doyle, Michael P.; Loh, K.-L.; DeVries, Keith M.; Chinn, Mitchell S.

doi:10.1016/s0040-4039(01)81001-7

Cited by 48 publications

(4 citation statements)

References 13 publications

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“…Rhodium(II) acetate [Rh 2 (OAc) 4 ] and rhodium(II) octanoate [Rh 2 (Oct) 4 ] were purchased from Strem Chemicals Inc., (Newburyport, MA) and dried under high vacuum (0.05 Torr) at 100 °C before use. Rhodium(II) acetamide [Rh 2 (acam) 4 ],26a rhodium(II) pivalate [Rh 2 (Piv) 4 ], and rhodium(II) perfluorobutyrate [Rh 2 (pfb) 4 ] were prepared according to literature procedures.…”

Section: Methodsmentioning

confidence: 99%

Rh(II)-Catalyzed Reaction Of Some α‘,α‘- and β‘-Branched-O-Alkyl α-(Alkoxycarbonyl)-α-diazoacetates

Wee

1997

J. Org. Chem.

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alpha',alpha'- and beta'- Branched-O-alkyl alpha-(alkoxycarbonyl)-alpha-diazoacetates 1a,b and 2a,b were prepared. The regio- and chemoselectivities in the Rh(II)-catalyzed reaction of these compounds were studied. The model systems 1a,b showed that the reactivity of the ester-substituted Rh(II) carbenoid is responsive to the nature of the Rh(II) catalyst; rhodium(II) acetamide favored insertion into the tertiary C-H bond and rhodium(II) perfluorobutyrate favored insertion into the secondary C-H bond. We also found that the nature of the O-alkyl group in the ester moiety had no influence on the reactivity of the Rh(II) carbenoid. In more complex systems such as compounds 2, it was found that rhodium(II) acetate promoted insertion into tertiary C-H bonds. Intramolecular cyclopropanation, to give 3-oxabicyclo[5.1.0]octane and 3-oxabicyclo[6.1.0]nonane products, was found to be competitive with tertiary C-H insertion; it is favored when rhodium(II) perfluorobutyrate was used as the catalyst. The Rh(II)-catalyzed reaction of 3 ("carbon" analog of 2a) resulted mainly in the cyclopentanone derivative, and no cyclopropanation product was detected. This result indicates that the ester oxygen in compounds of type 2 plays an important role in influencing the regio- and chemoselectivities of their reaction. Overall the results indicate that for compounds of a particular type of structure the regio- and chemoselectivities can be controlled via the judicious choice of the Rh(II) catalyst.

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Section: Methodsmentioning

confidence: 99%

Rh(II)-Catalyzed Reaction Of Some α‘,α‘- and β‘-Branched-O-Alkyl α-(Alkoxycarbonyl)-α-diazoacetates

Wee

1997

J. Org. Chem.

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“…1 (1S,2R)-N-Hydroxy-2-phenylcyclopropanecarboxamide (17). The synthesis involved following procedure A from (1S,2R)-ethyl 2phenylcyclopropanecarboxylate 70 (550 mg, 2.89 mmol). The residual gum obtained after workup was dissolved in DCM (10 mL), and the resulting white precipitate was collected by vacuum filtration and washed with DCM (2 × 5 mL).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Design, Synthesis, and Biological Evaluation of Potent and Selective Class IIa Histone Deacetylase (HDAC) Inhibitors as a Potential Therapy for Huntington’s Disease

Bürli¹,

Luckhurst²,

Aziz³

et al. 2013

J. Med. Chem.

136

138

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Inhibition of class IIa histone deacetylase (HDAC) enzymes have been suggested as a therapeutic strategy for a number of diseases, including Huntington's disease. Catalytic-site small molecule inhibitors of the class IIa HDAC4, -5, -7, and -9 were developed. These trisubstituted diarylcyclopropanehydroxamic acids were designed to exploit a lower pocket that is characteristic for the class IIa HDACs, not present in other HDAC classes. Selected inhibitors were cocrystallized with the catalytic domain of human HDAC4. We describe the first HDAC4 catalytic domain crystal structure in a "closed-loop" form, which in our view represents the biologically relevant conformation. We have demonstrated that these molecules can differentiate class IIa HDACs from class I and class IIb subtypes. They exhibited pharmacokinetic properties that should enable the assessment of their therapeutic benefit in both peripheral and CNS disorders. These selective inhibitors provide a means for evaluating potential efficacy in preclinical models in vivo.

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“…We chose to investigate the norcarane derivative 4 a , which was prepared in 70 % yield by a Pd 0 ‐catalyzed allylic alkylation4 (Scheme ; Ph 3 P, (C 2 H 5 ) 3 N, CH 2 Cl 2 , room temperature). The substrate 3 a for the alkylation is easily accessed from cyclohexene by typical cyclopropanation5 and chain‐extension protocols. An acetone solution of enyne 4 a was exposed to complex 2 (10 mol %) at ambient temperature for 6 h to ensure complete conversion, since the spots for the product and the starting material overlap on the TLC plate.…”

Section: Methodsmentioning

confidence: 99%

Constructing Tricyclic Compounds Containing a Seven-Membered Ring by Ruthenium-Catalyzed Intramolecular [5+2] Cycloaddition

Trost

Shen

2001

Angew. Chem.

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Polycyclic natural products that contain an embedded polyhydroazulene subunit, for example, dilatriol [1a] (1 a), rameswaralide [1b] (1 b), grayanotoxin [1c] (1 c), and phorbol [1d] (1 d), possess a diversity of biological activities. As such, they OH OH HO HO CH 3 OH H H H HO O O H CO 2 CH 3 OH H HO OH HO OH OH O OH HO H OH OH H 1a 1b 1c 1drepresent interesting yet demanding synthetic challenges and stimulate the development of new methodologies. The ability to increase molecular complexity rapidly by cycloaddition reactions should prove to be particularly interesting in offering short, atom-economical routes to such targets. Among these reactions, Rh- [2] and Ru-catalyzed [3] [52] cycloaddition reactions that involve cyclopropyl enynes have been discovered by the Wender group and by our group, respectively. We have shown that the Ru II catalyst 2 can catalyze this process under very mild conditions [3] (room temperature in acetone within a few hours). This fact encouraged us to examine the applicability of this strategy to complex targets represented by 1 a ± d, which raises a number of reactivity and selectivity issues that are addressed herein.The sensitivity of the Ru-catalyzed reactions to steric hindrance immediately led us to test the ability of 1,2,3trisubstituted cyclopropanes to participate in these reactions.

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Enhancement of stereoselectivity in catalytic cyclopropanation reactions

Cited by 48 publications

References 13 publications

Rh(II)-Catalyzed Reaction Of Some α‘,α‘- and β‘-Branched-O-Alkyl α-(Alkoxycarbonyl)-α-diazoacetates

Rh(II)-Catalyzed Reaction Of Some α‘,α‘- and β‘-Branched-O-Alkyl α-(Alkoxycarbonyl)-α-diazoacetates

Design, Synthesis, and Biological Evaluation of Potent and Selective Class IIa Histone Deacetylase (HDAC) Inhibitors as a Potential Therapy for Huntington’s Disease

Constructing Tricyclic Compounds Containing a Seven-Membered Ring by Ruthenium-Catalyzed Intramolecular [5+2] Cycloaddition

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