The transition-metal-catalyzed asymmetric addition of organometallic reagents to carbonyl compounds to produce enantiomer-enriched secondary or tertiary alcohols is a powerful tool for the construction of carbon-carbon bonds. Many organometallic reagents have been successfully used in this addition reaction.[1] However, a drawback for most organometallic reagents is their sensitivity to moisture and air, both of which impede the practical applications of these asymmetric carbon-carbon bond-forming reactions. As an exception, arylboronic acids are very stable to air and moisture. The catalytic enantioselective addition of arylboronic acids to carbonyl compounds has became a current focus for research, [1d] and a number of efficient chiral catalysts have been developed for the catalytic asymmetric addition of arylboronic acids to aldehydes [2] and aldimines.[3] However, the catalytic asymmetric addition of arylboronic acids to ketones, which are less active relative to aldehydes and aldimines, is more difficult, and only limited progress has been achieved. In 2006, Hayashi et al. reported the asymmetric addition of arylboronic acids to isatins, cyclic aketoamides, catalyzed by a rhodium/MeO-Mop (MeO-Mop = 2-methoxy-2'-diphenylphosphino-1,1'-binaphthyl) complex in high enantioselectivities (72-91 % ee).[4] By using a chiral phosphoramidite ligand derived from H 8 -binol (binol = 2,2'-dihydroxy-1,1'-binaphthyl), de Vries, Minnard, Feringa and et al. obtained 55 % ee in the same reaction.[5] The chiral phosphoramidite ligand was also used in the asymmetric addition of arylboronic acids to trifluoromethyl ketones with good enantioselectivities (50-83 % ee).[6] The intramolecular asymmetric addition of arylboronic acids to ketones catalyzed by a cationic palladium complex of binap (binap = 2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl) to give cyclic tertiary alcohols in high enantioselectivities (53-96 % ee) was reported by Lu et al. [7] To the best of our knowledge, the catalytic enantioselective addition of arylboronic acids to aketoesters to provide tertiary a-hydroxyesters has not yet been reported. [8] In the search for highly efficient methods to construct chiral 2-hydroxydiarylacetates, desirable chiral intermediates for the synthesis of antagonists of muscarinic receptors, [9] we became interested in the enantioselective addition of arylboronic acids to the a-aryl-and a-alkenyl-a-ketoesters. The Rh I /ShiP (ShiP = aryl(1,1'-spirobiindane-7,7'-diyl)phosphite) catalysts (1) recently developed by us [2c, 3b] were found to be highly efficient for this addition reaction to provide chiral tertiary a-hydroxyesters [10] in good yields and high enantiomeric excesses (up to 93 % ee).Preliminary experiments were carried out in H 2 O with catalyst generated in situ from 1.5 mol % [{RhCl-(CH 2 CH 2 ) 2 } 2 ][11] and 6 mol % (S)-1 a in the presence of two equivalents of LiF.[12] The addition of phenylboronic acid to ethyl 2-(4-chlorophenyl)-2-oxoacetate (2 a) at room temperature for 48 hours afforded tertiary a-hydroxyeste...

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A highly efficient copper-catalyzed enantioselective ring opening of oxabicylic alkenes with Grignard reagents has been developed by using chiral spiro phosphine ligands. Excellent trans selectivities, good yields, and high enantioselectivities are obtained for a broad range of Grignard reagents under mild reaction conditions. The catalyst system shows an extraordinary activity and the TON of the reaction reaches 9000.

The transition-metal-catalyzed asymmetric addition of organometallic reagents to carbonyl compounds to produce enantiomer-enriched secondary or tertiary alcohols is a powerful tool for the construction of carbon-carbon bonds. Many organometallic reagents have been successfully used in this addition reaction.[1] However, a drawback for most organometallic reagents is their sensitivity to moisture and air, both of which impede the practical applications of these asymmetric carbon-carbon bond-forming reactions. As an exception, arylboronic acids are very stable to air and moisture. The catalytic enantioselective addition of arylboronic acids to carbonyl compounds has became a current focus for research, [1d] and a number of efficient chiral catalysts have been developed for the catalytic asymmetric addition of arylboronic acids to aldehydes [2] and aldimines.[3] However, the catalytic asymmetric addition of arylboronic acids to ketones, which are less active relative to aldehydes and aldimines, is more difficult, and only limited progress has been achieved. In 2006, Hayashi et al. reported the asymmetric addition of arylboronic acids to isatins, cyclic aketoamides, catalyzed by a rhodium/MeO-Mop (MeO-Mop = 2-methoxy-2'-diphenylphosphino-1,1'-binaphthyl) complex in high enantioselectivities (72-91 % ee).[4] By using a chiral phosphoramidite ligand derived from H 8 -binol (binol = 2,2'-dihydroxy-1,1'-binaphthyl), de Vries, Minnard, Feringa and et al. obtained 55 % ee in the same reaction.[5] The chiral phosphoramidite ligand was also used in the asymmetric addition of arylboronic acids to trifluoromethyl ketones with good enantioselectivities (50-83 % ee).[6] The intramolecular asymmetric addition of arylboronic acids to ketones catalyzed by a cationic palladium complex of binap (binap = 2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl) to give cyclic tertiary alcohols in high enantioselectivities (53-96 % ee) was reported by Lu et al. [7] To the best of our knowledge, the catalytic enantioselective addition of arylboronic acids to aketoesters to provide tertiary a-hydroxyesters has not yet been reported. [8] In the search for highly efficient methods to construct chiral 2-hydroxydiarylacetates, desirable chiral intermediates for the synthesis of antagonists of muscarinic receptors, [9] we became interested in the enantioselective addition of arylboronic acids to the a-aryl-and a-alkenyl-a-ketoesters. The Rh I /ShiP (ShiP = aryl(1,1'-spirobiindane-7,7'-diyl)phosphite) catalysts (1) recently developed by us [2c, 3b] were found to be highly efficient for this addition reaction to provide chiral tertiary a-hydroxyesters [10] in good yields and high enantiomeric excesses (up to 93 % ee).Preliminary experiments were carried out in H 2 O with catalyst generated in situ from 1.5 mol % [{RhCl-(CH 2 CH 2 ) 2 } 2 ][11] and 6 mol % (S)-1 a in the presence of two equivalents of LiF.[12] The addition of phenylboronic acid to ethyl 2-(4-chlorophenyl)-2-oxoacetate (2 a) at room temperature for 48 hours afforded tertiary a-hydroxyeste...

No abstract