Pd(II)-Catalyzed Enantioselective C–H Activation of Cyclopropanes

Wasa, Masayuki; Engle, Keary M.; Lin, David W.; Yoo, Eun Jeong; Yu, Jin‐Quan

doi:10.1021/ja207607s

Cited by 379 publications

(121 citation statements)

References 38 publications

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“…Transition state 11a rather than 11b is preferred, in that the steric repulsion between the substituent on the newly generated chiral center (o-Tol) and the Boc group on the nitrogen center is minimized ( Figure 2). In 2011, Yu and coworkers reported the enantioselective C(sp 3 )-H activation of cyclopropanes catalyzed by Pd II /MPAA (Scheme 10) [44]. Scheme 10.…”

Section: Methodsmentioning

confidence: 99%

“…Screening of chiral mono-protected amino acid ligands [44]. With the optimized conditions, different cyclopropanes and organoboronic compounds were investigated and the products were obtained in good yields and good to excellent ee ( Figure 3).…”

Section: Methodsmentioning

confidence: 99%

“…Inspired by previous studies from Yu group [44,62], You et al, developed an enantioselective syntheses of planar chiral ferrocenes via palladium-catalyzed direct coupling with arylboronic acids in 2013 (Scheme 15) [72].…”

Section: Scheme 14mentioning

confidence: 99%

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Advances in Enantioselective C–H Activation/Mizoroki-Heck Reaction and Suzuki Reaction

et al. 2018

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Abstract:Traditional cross-coupling reactions, like Mizoroki-Heck Reaction and Suzuki Reaction, have revolutionized organic chemistry and are widely applied in modern organic synthesis. With the rapid development of C-H activation and asymmetric catalysis in recent years, enantioselective C-H activation/cross-coupling reactions have drawn much attention from researchers. This review summarizes recent advances in enantioselective C-H activation/Mizoroki-Heck Reaction and Suzuki Reaction, with emphasis on the structures and functions of chiral ligands utilized in different reactions.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Advances in Enantioselective C–H Activation/Mizoroki-Heck Reaction and Suzuki Reaction

et al. 2018

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“…In this case, organoboron coupling partners were used as the arylating agents. 10 Recently, the same research group discovered that (cyclopropylmethyl)amines are also attractive substrates …”

Section: Scheme 1 Diastereoselective Oxazoline-directed Iodinationmentioning

confidence: 99%

Diastereoselective Substrate-Controlled Transition-Metal-Catalyzed C–H Activation: An Old Solution to a Modern Synthetic Challenge

Wencel‐Delord

Colobert

2015

Synlett

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The synthesis of chiral compounds by means of asymmetric C-H activation is an appealing modern strategy for the straightforward conversion of simple and nonfunctionalized substrates into high-valueadded stereogenic molecules. For several years, considerable attention has been focused on the design of enantioselective transformations involving the use of chiral ligands as sources of chirality. In addition, a complementary strategy based on direct functionalization of substrates bearing a chiral element has recently demonstrated its potential. Such diastereoselective transformations can be achieved by incorporating a chiral auxiliary into a directing group (DG). Alternatively, direct functionalization of chiral-pool molecules, such as α-amino acids, provides a valuable synthetic route to novel non-natural amino acid derivatives. The aim of this account is to highlight major achievements in diastereoselective C-H activation. Particular attention will be paid to the contributions of our group in this emerging field.

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“…Yu and co-workers reported enantioselective, palladium-catalyzed arylation and alkylation reactions of cyclopropanes containing N-aryl or triflyl amide as a directing group with organoborane or iodoarene reagents. [14,15] In addition, Cramer and co-workers reported Pd-catalyzed intramolecular arylations and alkylation of cyclopropyl C-H bonds to form tetrahydroquinolines, dihydroquinolones, dihydroisoquinolones and γ-lactams. [16][17][18] However, enantioselective functionalization to form products containing a new carbonheteroatom bond has not been reported.…”

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confidence: 99%

Rhodium‐Catalyzed Enantioselective Silylation of Cyclopropyl C−H Bonds

Lee

Hartwig

2016

Angewandte Chemie

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We describe an enantioseleclive silylation of cyclopropanes catalyzed by a rhodium precursor and the bisphosphine (S)-DTBM-SEGPHOS. (Hydrido)silyl ethers, generated in situ by the dehydrogenative silylation of cyclopropylmethanols with diethylsilane, undergo asymmetric, intramolecular silylation of cyclopropyl C-H bonds in high yields with high enantiomeric excesses in the presence of the rhodium catalyst. The resulting enantioenriched oxasilolanes are suitable substrates for Tamao-Fleming oxidation to form cyclopropanols with conservation of the ee from the C-H bond silylation. Preliminary mechanistic data suggest that C-H cleavage is likely to be the turnover-limiting and enantioselectivity-determining step. Graphical Abstract(Hydrido)silyl ethers, generated in situ by the dehydrogenative silylation of cyclopropylmethanols with diethylsilane, undergo asymmetric, intramolecular silylation of cyclopropyl C-H bonds in high yields with high enantiomeric excesses in the presence of a rhodium catalyst. The silylation products are suitable substrates for Tamao-Fleming oxidation to form cyclopropanols with conservation of the ee from the C-H bond silylation.Keywords asymmetric catalysis; C-H activation; cyclopropane; rhodium; silylation The functionalization of C-H bonds with boranes and silanes has been studied intensively, due to the high regioselectivity of these processes for sterically accessible C-H bonds and widespread utility of the products. [1,2] However, the development of enantioselective variants of these reactions, particularly enantioselective functionalization of alkyl C-H bonds, has been limited (Scheme 1). [3][4][5] Kuninobu, Murai and Takai reported the Correspondence to: John F. Hartwig, jhartwig@berkeley.edu. Supporting information for this article is given via a link at the end of the document. HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript asymmetric silylation of a C-H bond to generate a stereogenic silicon center with up-to 88% enantiomeric excess (ee) (Scheme 1A). [6,7] Shibata, He, Murai and Takai independently reported the synthesis of planar chiral compounds with moderate to high enantioselectivities by asymmetric C-H silylation of ferrocenes. [8][9][10] Recently, we reported an enantioselective silylation of aryl C-H bonds to form enantioenriched benzoxasilole products with up-to 99% ee. [11] Although these reactions can occur with high enantioselectivity, they are limited to the functionalization of aryl C-H bonds. The only published set of enantioselective silylations of alkyl C-H bonds occurs with low ee (37-40% ee) and with limited scope (Scheme 1B). [12] To create the first silylations of alkyl C-H bonds that occur with high enantioselectivity, we investigated systems for the reactions of cyclopropanes. C-H bonds of cyclopropanes are more reactive than sp 3 C-H bonds of unstrained rings or alkyl chains, [13] and the rigid conformation of a cyclopropane could allow for high stereoselectivity. Yu and co-workers reported enantioselective...

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Pd(II)-Catalyzed Enantioselective C–H Activation of Cyclopropanes

Cited by 379 publications

References 38 publications

Advances in Enantioselective C–H Activation/Mizoroki-Heck Reaction and Suzuki Reaction

Advances in Enantioselective C–H Activation/Mizoroki-Heck Reaction and Suzuki Reaction

Diastereoselective Substrate-Controlled Transition-Metal-Catalyzed C–H Activation: An Old Solution to a Modern Synthetic Challenge

Rhodium‐Catalyzed Enantioselective Silylation of Cyclopropyl C−H Bonds

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