ChemInform Abstract: Copper‐Catalyzed Borylation Reactions of Alkynes and Arynes.

Yoshida, Hiroto; Kawashima, Shota; Takemoto, Yumi; Okada, Kengo; Ohshita, Joji; Takaki, Ken

doi:10.1002/chin.201219187

Cited by 2 publications

(2 citation statements)

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“…The reaction afforded ring‐opened monoborylalkene 8 a as the sole coupling product. In contrast, the copper‐catalyzed carboboration of an alkyne with 7 afforded allyl(cyclopropyl) monoborylalkenes, such as 8 b , through an S N 2 pathway 7f. Carboboration using diethyl 2‐allyl‐2‐(2‐bromoethyl)malonate 9 , possessing a terminal double bond, was accompanied by a cyclization reaction (Scheme ).…”

Section: Methodsmentioning

confidence: 99%

Iron‐Catalyzed Diboration and Carboboration of Alkynes

Nakagawa

Hatakeyama

Nakamura

2015

Chemistry A European J

110

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An iron-catalyzed diboration reaction of alkynes with bis(pinacolato)diboron (B2pin2) and external borating agents (MeOB(OR)2) affords diverse symmetrical or unsymmetrical cis-1,2-diborylalkenes. The simple protocol for the diboration reaction can be extended to the iron-catalyzed carboboration of alkynes with primary and, unprecedentedly, secondary alkyl halides, affording various tetrasubstituted monoborylalkenes in a highly stereoselective manner. DFT calculations indicate that a boryliron intermediate adds across the triple bond of an alkyne to afford an alkenyliron intermediate, which can react with the external trapping agents, borates and alkyl halides. In situ trapping experiments support the intermediacy of the alkenyl iron species using radical probe stubstrates.

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Section: Methodsmentioning

confidence: 99%

Iron‐Catalyzed Diboration and Carboboration of Alkynes

Nakagawa

Hatakeyama

Nakamura

2015

Chemistry A European J

110

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“…Our preliminary studies used phenyl-substituted N-sulfonyl ynamide 1a with 1,3-dimethylimidazol-2-ylidene borane 2 as model systems. In the initial experiments, the CuCl/t-BuOK-catalyzed hydroboration of 1a and 2 at 70 C with phosphine ligands (Lee et al, 2008;Yoshida et al, 2012) did not produce any detectable amount of the desired product 3a (Table 1, entries 1-2). In addition, when the hydroboration of 1a and 2 was catalyzed by NHC-CuCl/t-BuOK system (Park et al, 2012), the desired product 3a was not obtained either (entry 3).…”

Section: Optimization Of Reaction Conditionsmentioning

confidence: 99%