Highly Diastereoselective Reductive Coupling of 2-Bromo-2,3,3,3-tetrafluoropropanamide with Aldehydes Promoted by Triphenylphosphine−Titanium(IV) Isopropoxide. An Efficient Route to the Synthesis of erythro-α-Fluoro-α-(trifluoromethyl)-β-hydroxy Amides
摘要:
The reductive coupling reaction of N-methoxy-N-methyl-2-bromo-2,3,3,3-tetrafluoropropanamide (Weinreb amide) with various aldehydes under the influence of the combined reagent, 1.2 equiv each of triphenylphosphine and titanium(IV) isopropoxide, took place smoothly at ambient temperature to give the corresponding alpha-fluoro-alpha-(trifluoromethyl)-beta-hydroxy amides in a highly erythro-selective manner. The high erythro selectivity was also obtained even by employing a combination of triphenylphosphine (1.2 equiv) and a catalytic amount of titanium(IV) isopropoxide.
Highly Diastereoselective Reductive Coupling of 2-Bromo-2,3,3,3-tetrafluoropropanamide with Aldehydes Promoted by Triphenylphosphine−Titanium(IV) Isopropoxide. An Efficient Route to the Synthesis of erythro-α-Fluoro-α-(trifluoromethyl)-β-hydroxy Amides
摘要:
The reductive coupling reaction of N-methoxy-N-methyl-2-bromo-2,3,3,3-tetrafluoropropanamide (Weinreb amide) with various aldehydes under the influence of the combined reagent, 1.2 equiv each of triphenylphosphine and titanium(IV) isopropoxide, took place smoothly at ambient temperature to give the corresponding alpha-fluoro-alpha-(trifluoromethyl)-beta-hydroxy amides in a highly erythro-selective manner. The high erythro selectivity was also obtained even by employing a combination of triphenylphosphine (1.2 equiv) and a catalytic amount of titanium(IV) isopropoxide.
Highly Stereoselective Aldol-type Reaction of 2-Bromo-2,3,3,3-tetrafluoropropanamide with Aldehydes Leading to<i>erythro</i>-α-Fluoro-α-(trifluoromethyl)-β-hydroxy Amides
N-Methoxy-N-methyl-2-bromo-2,3,3,3-tetrafluoropropanamide underwent highly stereoselective aldol-type reaction with various aldehydes under the influence of triphenylphosphine—a catalytic amount of titanium(IV) isopropoxide at room temperature to give the erythro-isomers of α-fluoro-α-(trifluoromethyl)-β-hydroxy amides preferentially in good to excellent yields.
Highly Diastereoselective Reductive Coupling of 2-Bromo-2,3,3,3-tetrafluoropropanamide with Aldehydes Promoted by Triphenylphosphine−Titanium(IV) Isopropoxide. An Efficient Route to the Synthesis of <i>e</i><i>rythro</i>-α-Fluoro-α-(trifluoromethyl)-β-hydroxy Amides
The reductive coupling reaction of N-methoxy-N-methyl-2-bromo-2,3,3,3-tetrafluoropropanamide (Weinreb amide) with various aldehydes under the influence of the combined reagent, 1.2 equiv each of triphenylphosphine and titanium(IV) isopropoxide, took place smoothly at ambient temperature to give the corresponding alpha-fluoro-alpha-(trifluoromethyl)-beta-hydroxy amides in a highly erythro-selective manner. The high erythro selectivity was also obtained even by employing a combination of triphenylphosphine (1.2 equiv) and a catalytic amount of titanium(IV) isopropoxide.