Construction of 1-Heteroaryl-3-azabicyclo[3.1.0]hexanes by sp<sup>3</sup>–sp<sup>2</sup> Suzuki–Miyaura and Chan–Evans–Lam Coupling Reactions of Tertiary Trifluoroborates

Harris, Michael; Li, Qifang; Lian, Yajing; Xiao, Jun; Londregan, Allyn T.

doi:10.1021/acs.orglett.7b01097

Cited by 54 publications

(38 citation statements)

References 38 publications

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“…Furthermore, (vinyl)Bpin reacted to form spirocyclic organoboron reagents (products 32-33) that could potentially serve as nucleophilic partners in cross-coupling reactions. [13] The relatively high reactivity of 1,3-dienes compared to monoalkenes can be leveraged to carry out a selective monocyclopropanation of a triene substrate (product 35, 71% yield). The resulting product was then subjected to Rh-catalyzed [5 + 2]cycloaddition conditions to arrive at tricyclic product 36 in 47% yield.…”

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confidence: 99%

Cobalt Catalyzed Reductive Spirocyclopropanation Reactions

2019

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Cobalt pyridineÀ diimine (PDI) complexes catalyze the reductive spirocyclopropanation of terminal 1,3-dienes. gem-Dichlorocycloalkanes serve as carbene precursors and Zn is used as a terminal electron source. The reaction is effective for a range of gem-dichloro partners including those containing sulfur and nitrogen heterocycles. An example of an intramolecular Rh-catalyzed [5 + 2]cycloaddition of a vinyl spirocyclopropane is demonstrated, providing rapid access to a complex tricyclic framework. Overall, this catalyst system is capable of suppressing the kinetically facile 1,2hydride shift, which has hampered the development of SimmonsÀ Smith reactions using Zn carbenoids possessing β-hydrogen atoms.

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confidence: 99%

Cobalt Catalyzed Reductive Spirocyclopropanation Reactions

2019

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“…The chiral tertiary boronic ester is easily converted to the corresponding trifluoroborate salt 17 (87%), 13 the latter are generally more stable than pinacol boronates and are of interest in metal-catalyzed cross-coupling chemistry. 14,15 Oxidation of 6a by NaBO 3 .4H 2 O affords the chiral tertiary alcohol 18a (90%, 97:3 er). Protodeboronation 16 of 6a using TBAF/H 2 O yields the known chiral phosphonate 19 (85%, 96:4 er).…”

Section: Resultsmentioning

confidence: 99%

Phosphonate-Directed Catalytic Asymmetric Hydroboration: Delivery of Boron to the More Substituted Carbon, Leading to Chiral Tertiary Benzylic Boronic Esters

Chakrabarty

Takacs

2018

ACS Catal.

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Phosphonate-directed catalytic asymmetric hydroboration (CAHB) of β-aryl/heteroaryl methylidenes and trisubstituted alkenes by pinacolborane enables facile access to functionalized, chiral tertiary benzylic boronic esters. Hydroboration is catalyzed by a chiral rhodium catalyst prepared in situ from a Rh(I)-precursor in combination with a simple TADDOL-derived chiral cyclic monophosphite in a 1:1 ratio. The regio- and stereochemistry arises from the combined effects of the relative disposition of the directing group to the alkene, the alkene substitution pattern, and the necessity of an aryl substituent attached to the alkene. A range of aryl and heteroaryl substituents can be accommodated, and for several chiral substrates, the reactions are efficiently catalyst-controlled enabling the choice of diastereomeric products as desired. Stereospecific transformations of the chiral boronic ester afford chiral phosphonates bearing a quaternary carbon stereocenter. The synthetic utility of the products is further demonstrated by α-oxidation of the phosphonate leading to hydroxy- and oxo-phosphonates; the latter readily undergo elimination/substitution reactions to unmask the phosphonate functionality with the formation of aldehydes, alcohols, esters, amides, acids and ketones.

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“…This dual catalysis relies on a single-electron transmetalation and provides a complementary toolbox to the classical couplings Harris et al recently reported a Pd-catalyzed SMC reaction with tertiary trifluoroborate salts to synthesize 1-heteroaryl-3-azabicyclo[3.1.0]hexanes 51, an interesting scaffold in medicinal studies with limited synthetic approaches. The SMC protocol was compatible with a range of aryl and heteroaryl chlorides and bromides 50 (Scheme 9C) [99]. The optimized conditions involved CatacXium-A-Pd-G3, Cs 2 CO 3 in toluene/water and were applied in synthesis of 18 examples with good to excellent yields.…”

Section: Organotrifluoroborates In Sp 3 -Sp 2 Smcsmentioning

confidence: 99%

Recent Advances in Metal-Catalyzed Alkyl–Boron (C(sp3)–C(sp2)) Suzuki-Miyaura Cross-Couplings

El‐Maiss

Dine

et al. 2020

Catalysts

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Boron chemistry has evolved to become one of the most diverse and applied fields in organic synthesis and catalysis. Various valuable reactions such as hydroborylations and Suzuki–Miyaura cross-couplings (SMCs) are now considered as indispensable methods in the synthetic toolbox of researchers in academia and industry. The development of novel sterically- and electronically-demanding C(sp3)–Boron reagents and their subsequent metal-catalyzed cross-couplings attracts strong attention and serves in turn to expedite the wheel of innovative applications of otherwise challenging organic adducts in different fields. This review describes the significant progress in the utilization of classical and novel C(sp3)–B reagents (9-BBN and 9-MeO-9-BBN, trifluoroboronates, alkylboranes, alkylboronic acids, MIDA, etc.) as coupling partners in challenging metal-catalyzed C(sp3)–C(sp2) cross-coupling reactions, such as B-alkyl SMCs after 2001.

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Construction of 1-Heteroaryl-3-azabicyclo[3.1.0]hexanes by sp³–sp² Suzuki–Miyaura and Chan–Evans–Lam Coupling Reactions of Tertiary Trifluoroborates

Cited by 54 publications

References 38 publications

Cobalt Catalyzed Reductive Spirocyclopropanation Reactions

Cobalt Catalyzed Reductive Spirocyclopropanation Reactions

Phosphonate-Directed Catalytic Asymmetric Hydroboration: Delivery of Boron to the More Substituted Carbon, Leading to Chiral Tertiary Benzylic Boronic Esters

Recent Advances in Metal-Catalyzed Alkyl–Boron (C(sp3)–C(sp2)) Suzuki-Miyaura Cross-Couplings

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Construction of 1-Heteroaryl-3-azabicyclo[3.1.0]hexanes by sp3–sp2 Suzuki–Miyaura and Chan–Evans–Lam Coupling Reactions of Tertiary Trifluoroborates

Cited by 54 publications

References 38 publications

Cobalt Catalyzed Reductive Spirocyclopropanation Reactions

Cobalt Catalyzed Reductive Spirocyclopropanation Reactions

Phosphonate-Directed Catalytic Asymmetric Hydroboration: Delivery of Boron to the More Substituted Carbon, Leading to Chiral Tertiary Benzylic Boronic Esters

Recent Advances in Metal-Catalyzed Alkyl–Boron (C(sp3)–C(sp2)) Suzuki-Miyaura Cross-Couplings

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Construction of 1-Heteroaryl-3-azabicyclo[3.1.0]hexanes by sp³–sp² Suzuki–Miyaura and Chan–Evans–Lam Coupling Reactions of Tertiary Trifluoroborates