- Diphenylprolinol silyl ether as a catalyst in an asymmetric, catalytic and direct α-benzoyloxylation of aldehydes
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Diphenylprolinol silyl ether was found to promote asymmetric, catalytic and direct α-benzoyloxylation of aldehydes with benzoyl peroxide to afford oxidized products in good yields with excellent enantioselectivity. The Royal Society of Chemistry 2009.
- Gotoh, Hiroaki,Hayashi, Yujiro
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supporting information; experimental part
p. 3083 - 3085
(2009/12/01)
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- Organocatalytic α-oxybenzoylation of aldehydes
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A simple method for the asymmetric α-oxybenzoylation of aldehydes is presented. Treatment of a series of aldehydes with benzoyl peroxide in the presence of a MacMillan imidazolidinone leads directly to the α-oxybenzoylated product with excellent levels of
- Vaismaa, Matti J.P.,Yau, Sze Chak,Tomkinson, Nicholas C.O.
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scheme or table
p. 3625 - 3627
(2009/09/30)
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- Kinetic resolution of 1,2-diols using nitrogen-tethered bisimidazoline-copper(I) catalyzed benzoylation
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Nitrogen-tethered bisimidazoline (Nb-imidazoline) ligand was utilized in the Cu(I)-catalyzed benzoylation of 1,2-diols. With the assistance of i-Pr2NEt, the reaction of rac-1,2-diols with o-methylbenzoyl chloride was smoothly catalyzed by Nb-imidazoline-CuCl in CH2Cl2 to give the corresponding o-methylbenzoylated secondary alcohols in up to 79% ee.
- Arai, Takayoshi,Mizukami, Tomoe,Mishiro, Asami,Yanagisawa, Akira
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experimental part
p. 995 - 1000
(2009/06/28)
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- Lipase-catalyzed alcoholysis of diol dibenzoates: Selective enzymatic access to the 2-benzoyl ester of 1,2-propanediol and preparation of the enantiomerically pure (R)-1-O-benzoyl-2-methylpropane-1,3-diol
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Enzymatic debenzoylation of 1,2-propanediol dibenzoate with 1-octanol has been studied in organic solvent using lipases from different sources. In general a slow, highly regioselective alcoholysis in diisopropyl ether affords exclusively a monoester benzoylated at the secondary hydroxy group although the reaction proceeds with low enantioselectivity. In the presence of Pseudomonas cepacia lipase absorbed onto celite, a faster reaction allows the preparation of the 2-benzoyl ester of (R)-1,2-propanediol (82% ee) and the enantiomerically pure (R)-1-O-benzoyl-2-methylpropane-1,3-diol (>98% ee).
- Santaniello, Enzo,Casati, Silvana,Ciuffreda, Pierangela,Gamberoni, Luca
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p. 1705 - 1708
(2007/10/03)
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- Chemoselective Benzoylations of 1,2-Diols. Reactivity Comparisons of Reagents. Triphenylphosphine-Benzoyl Peroxide and Triphenylphosphine-Diethyl Azodicarboxylate-Benzoic Acid
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The triphenylphosphine-benzoyl peroxide (TPP-BPO) reagent initiates stereospecific benzoylation of secondary carbinol stereocenters with essentially complete inversion of stereochemistry.Monobenzoylations of 1,2-propanediol and styrene glycol with TPP-BPO and triphenylphosphine-diethyl azodicarboxylate-benzoic acid reagents afford a predominance of the more sterically encumbered C-2 benzoate with complete inversion of stereochemistry.Formation of a quintessential 1,3,2λ5-dioxaphospholane intermediate, followed by proton-assisted and highly stereoselective ring opening of the phospholanes to isomeric oxyphosphonium ions, allows for Arbusov displacement of triphenylphosphine oxide by benzoate anion.This rationale adequately accounts for both the high chemoselectivity and the stereochemistry of the reactions.
- Pautard, Anne M.,Evans, Slayton A.
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p. 2300 - 2303
(2007/10/02)
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