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Asymmetric propargylation of ketones using allenylboronates catalyzed by chiral biphenols.

ABSTRACT: Chiral biphenols catalyze the enantioselective asymmetric propargylation of ketones using allenylboronates. The reaction uses 10 mol % of 3,3'-Br(2)-BINOL as the catalyst and allenyldioxoborolane as the nucleophile, in the absence of solvent, and under microwave irradiation to afford the homopropargylic alcohol. The reaction products are obtained in good yields (60-98%) and high enantiomeric ratios (3:1-99:1). Diastereoselective propargylations using chiral racemic allenylboronates result in good diastereoselectivities (dr >86:14) and enantioselectivities (er >92:8) under the catalytic conditions.

SUBMITTER: Barnett DS

PROVIDER: S-EPMC3155969 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Asymmetric propargylation of ketones using allenylboronates catalyzed by chiral biphenols.

Barnett David S DS Schaus Scott E SE

Organic letters 20110706 15

Chiral biphenols catalyze the enantioselective asymmetric propargylation of ketones using allenylboronates. The reaction uses 10 mol % of 3,3'-Br(2)-BINOL as the catalyst and allenyldioxoborolane as the nucleophile, in the absence of solvent, and under microwave irradiation to afford the homopropargylic alcohol. The reaction products are obtained in good yields (60-98%) and high enantiomeric ratios (3:1-99:1). Diastereoselective propargylations using chiral racemic allenylboronates result in goo ...[more]

PMID: 21732609

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