Intermolecular/Intramolecular Sequential Aldol Reaction

The first example of intermolecular/intramolecular sequential aldol reaction of disilyl enol ethers is described. This strategy enables the formation of five-, six-, and seven-membered ring products. Four or more contiguous stereogenic centers are created with high levels of relative stereochemical control

Intermolecular/Intramolecular Sequential Aldol Reaction

The first example of intermolecular/intramolecular sequential aldol reaction of disilyl enol ethers is described. This strategy enables the formation of five-, six-, and seven-membered ring products. Four or more contiguous stereogenic centers are created with high levels of relative stereochemical control

Intermolecular/Intramolecular Sequential Aldol Reaction

The first example of intermolecular/intramolecular sequential aldol reaction of disilyl enol ethers is described. This strategy enables the formation of five-, six-, and seven-membered ring products. Four or more contiguous stereogenic centers are created with high levels of relative stereochemical control

Intermolecular/Intramolecular Sequential Aldol Reaction

The first example of intermolecular/intramolecular sequential aldol reaction of disilyl enol ethers is described. This strategy enables the formation of five-, six-, and seven-membered ring products. Four or more contiguous stereogenic centers are created with high levels of relative stereochemical control

Catalytic Asymmetric Three-Component Mannich-Type Reaction of Alkenyl Trichloroacetates

A catalytic enantioselective three-component Mannich-type reaction of alkenyl trichloroacetates, ethyl glyoxalate, and aniline derivatives was achieved using an (S)-BINOL-derived chiral tin dibromide possessing a 4-trifluoromethylphenyl group at the 3- and 3′-positions as the chiral precatalyst in the presence of sodium ethoxide, sodium iodide, and ethanol. Optically active β-amino ketones with up to 98% ee were syn-selectively obtained in high yields even from imines possessing a polar amino group under the influence of the in situ generated chiral tin bromide ethoxide

Catalytic Asymmetric Three-Component Mannich-Type Reaction of Alkenyl Trichloroacetates

A catalytic enantioselective three-component Mannich-type reaction of alkenyl trichloroacetates, ethyl glyoxalate, and aniline derivatives was achieved using an (S)-BINOL-derived chiral tin dibromide possessing a 4-trifluoromethylphenyl group at the 3- and 3′-positions as the chiral precatalyst in the presence of sodium ethoxide, sodium iodide, and ethanol. Optically active β-amino ketones with up to 98% ee were syn-selectively obtained in high yields even from imines possessing a polar amino group under the influence of the in situ generated chiral tin bromide ethoxide

Stereodivergent Synthesis of 1,3-Dienes via Protodeboronation of Homoallenylboronic Esters

Vinylboronic esters and allylboronic esters are well known to afford olefins by protodeboronation, and therefore homoallenylboronic esters should be similarly available as precursors for 1,3-dienes, but this strategy has not been well explored due to the limited availability of homoallenylboronic esters. Here, we describe a versatile synthesis of homoallenylboronic esters via lithiation–borylation and subsequent 1,2-rearrangement. The resulting homoallenylboronic esters were successfully converted into Z- and E-1,3-dienes by protodeboronation using Bu4NF and B­(C6F5)3/PhOH, respectively

Boron Tribromide-Assisted Chiral Phosphoric Acid Catalyst for a Highly Enantioselective Diels–Alder Reaction of 1,2-Dihydropyridines

BBr₃–chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Brønsted acid (LBA) catalysts for promoting the enantio­selective Diels–Alder (DA) reaction of α-substituted acroleins and α-CF₃ acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydro­pyridines gave the corresponding optically active isoquinuclidines with high enantio­selectivities. Moreover, transformations to the key intermediates of indole alkaloids, catharanthine and allocatharanthine, are demonstrated

Boron Tribromide-Assisted Chiral Phosphoric Acid Catalyst for a Highly Enantioselective Diels–Alder Reaction of 1,2-Dihydropyridines

BBr₃–chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Brønsted acid (LBA) catalysts for promoting the enantio­selective Diels–Alder (DA) reaction of α-substituted acroleins and α-CF₃ acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydro­pyridines gave the corresponding optically active isoquinuclidines with high enantio­selectivities. Moreover, transformations to the key intermediates of indole alkaloids, catharanthine and allocatharanthine, are demonstrated

Boron Tribromide-Assisted Chiral Phosphoric Acid Catalyst for a Highly Enantioselective Diels–Alder Reaction of 1,2-Dihydropyridines

BBr₃–chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Brønsted acid (LBA) catalysts for promoting the enantio­selective Diels–Alder (DA) reaction of α-substituted acroleins and α-CF₃ acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydro­pyridines gave the corresponding optically active isoquinuclidines with high enantio­selectivities. Moreover, transformations to the key intermediates of indole alkaloids, catharanthine and allocatharanthine, are demonstrated