Enantioselective Synthesis of Hydrothiazole Derivatives via an Isocyanide-Based Multicomponent Reaction

Catalytic asymmetric synthesis of hydrothiazole derivatives was developed via a well-organized formal [2 + 1 + 2] cycloaddition reaction triggered by asymmetric addition of isocyanide to alkylidene malonate. Various chiral hydrothiazole derivatives were readily provided in good yield with high enantioselectivity (up to 98% yield, 98.5:1.5 er) utilizing a chiral Mg­(OTf)2/N,N′-dioxide complex as the catalyst under mild conditions. Based on the experimental studies and the structure of the catalyst, a possible catalytic cycle was proposed to elucidate the reaction process and activation mode

Asymmetric Organocatalytic Cyclopropanation of Cinnamone Derivatives with Stabilized Sulfonium Ylides

A simple chiral diamine catalyst 1h was successfully applied in the asymmetric cyclopropanation of cinnamone derivatives with stabilized sulfur ylides. The desired cyclopropanation adducts were obtained in moderate yields (up to 68%) with good enantioselectivities (67–93% ee) and excellent diastereoselectivities (>95:5) under mild conditions

Asymmetric Synthesis of 3,4-Diaminochroman-2-ones Promoted by Guanidine and Bisguanidium Salt

A highly enantioselective synthesis of 3,4-diaminochroman-2-ones has been realized via the domino reaction of o-hydroxy aromatic aldimines and azlactones. Notably, a cis-product was obtained as the major product by the use of guanidine 2a whereas a trans-product was the major product with bisguanidium salt 3•HBArF4. In two cases, various substituted 3,4-dihydrocoumarins were obtained with high yields (up to 99%) as well as excellent enantioselectivities (up to 99% ee) and diastereoselectivities (up to >99:1 cis:trans and 98:2 trans:cis, respectively) under mild reaction conditions

Asymmetric Synthesis of 3,4-Diaminochroman-2-ones Promoted by Guanidine and Bisguanidium Salt

A highly enantioselective synthesis of 3,4-diaminochroman-2-ones has been realized via the domino reaction of o-hydroxy aromatic aldimines and azlactones. Notably, a cis-product was obtained as the major product by the use of guanidine 2a whereas a trans-product was the major product with bisguanidium salt 3•HBArF4. In two cases, various substituted 3,4-dihydrocoumarins were obtained with high yields (up to 99%) as well as excellent enantioselectivities (up to 99% ee) and diastereoselectivities (up to >99:1 cis:trans and 98:2 trans:cis, respectively) under mild reaction conditions

Asymmetric Organocatalytic Cyclopropanation of Cinnamone Derivatives with Stabilized Sulfonium Ylides

A simple chiral diamine catalyst <b>1h</b> was successfully applied in the asymmetric cyclopropanation of cinnamone derivatives with stabilized sulfur ylides. The desired cyclopropanation adducts were obtained in moderate yields (up to 68%) with good enantioselectivities (67–93% <i>ee</i>) and excellent diastereoselectivities (>95:5) under mild conditions

Asymmetric Synthesis of 3,4-Diaminochroman-2-ones Promoted by Guanidine and Bisguanidium Salt

A highly enantioselective synthesis of 3,4-diaminochroman-2-ones has been realized via the domino reaction of o-hydroxy aromatic aldimines and azlactones. Notably, a cis-product was obtained as the major product by the use of guanidine 2a whereas a trans-product was the major product with bisguanidium salt 3•HBArF4. In two cases, various substituted 3,4-dihydrocoumarins were obtained with high yields (up to 99%) as well as excellent enantioselectivities (up to 99% ee) and diastereoselectivities (up to >99:1 cis:trans and 98:2 trans:cis, respectively) under mild reaction conditions

Correction to “Organocatalytic Oxyamination of Azlactones: Kinetic Resolution of Oxaziridines and Asymmetric Synthesis of Oxazolin-4-ones”

Correction to “Organocatalytic Oxyamination of Azlactones: Kinetic Resolution of Oxaziridines and Asymmetric Synthesis of Oxazolin-4-ones

Enantioselective Synthesis of 4‑Hydroxy-dihydrocoumarins via Catalytic Ring Opening/Cycloaddition of Cyclobutenones

A highly diastereo- and enantioselective ring-opening/cycloaddition reaction of cyclobutenones with 2-hydroxyacetophenones or salicylaldehyde was achieved by employing a chiral N,N′-dioxide-scandium­(III) complex as the catalyst. It provided various 3-phenylvinyl-4-hydroxy-dihydrocoumarins in good yields (up to 92%), high enantioselectivities (up to 93% ee), and excellent diastereoselectivities (>19:1 dr). Moreover, a possible catalytic cycle was proposed based on the control experiments and previous reports