Asymmetric Base Organocatalysis

Kondoh, Azusa; Terada, Masahiro

doi:10.1002/9781119736424.ch3

Cited by 4 publications

(4 citation statements)

References 174 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have previously developed a Brønsted base catalyzed addition reaction of homoenolate equivalents in which allylic alcohols having a diethoxyphosphoryl group at the α-position are used as precursors of homoenolate equivalents (Scheme 1a ). 5 In the reaction, α-oxygenated allyl anions, generated through deprotonation and a subsequent [1,2]-phospha-Brook rearrangement, 6 react with electrophiles at the γ-position to provide alkenyl phosphates. The adducts are then converted by solvolysis into ketones, which are the formal adducts of homoenolates with electrophiles.…”

Section: Table 1 Screening Of Reaction Conditions ...mentioning

confidence: 99%

Brønsted Base Catalyzed Conjugate Addition of β-Acylvinyl Anion Equivalents to α,β-Unsaturated Ketones

Kondoh

Yamaguchi

Watanabe

et al. 2022

Synlett

Self Cite

View full text Add to dashboard Cite

A Brønsted base-catalyzed addition reaction of allyl sulfones having a diethoxyphosphoryloxy group, which are new precursors of β-acylvinyl anion equivalents, with chalcone derivatives was developed. The reaction proceeded efficiently under the influence of phosphazene base P2-tBu as the catalyst. This is a rare example of a catalytic addition reaction of β-acylvinyl anion equivalents. A preliminary study on an asymmetric variant was also conducted with a chiral bis(guanidino)iminophosphorane catalyst.

show abstract

Section: Table 1 Screening Of Reaction Conditions ...mentioning

confidence: 99%

Brønsted Base Catalyzed Conjugate Addition of β-Acylvinyl Anion Equivalents to α,β-Unsaturated Ketones

Kondoh

Yamaguchi

Watanabe

et al. 2022

Synlett

Self Cite

View full text Add to dashboard Cite

show abstract

“…[4] Because of their functionalities, guanidine compounds are used as organocatalysts, and chiral guanidine compounds have been widely applied for asymmetric organocatalytic reactions. [5] In this account, we describe our recent research on applications of guanidinium hypoiodite salts in oxidative functionalization at the α-position of carbonyl compounds. The de novo catalytic system can catalyze both carbonheteroatom bond-forming reactions and oxidative carboncarbon bond-forming reactions, which are still challenging reactions in conventional catalysis-based strategies.…”

Section: Introductionmentioning

confidence: 99%

Exploring Guanidinium Organocatalysts for Hypoiodite‐Mediated Reactions

Odagi

Nagasawa

2023

The Chemical Record

View full text Add to dashboard Cite

This account describes our recent work on developing guanidinium hypoiodite‐ catalysts for oxidative carbon‐nitrogen and carbon‐carbon bond‐forming reactions. These reactions proceeded smoothly using guanidinium hypoiodite generated in situ by treating 1,3,4,6,7‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidine hydroiodide salts with an oxidant. In this approach, the ionic interaction and hydrogen bonding ability of the guanidinium cations enable bond‐forming reactions that have been difficult with conventional methods. Enantioselective oxidative carbon‐carbon bond‐forming reaction was also achieved by using a chiral guanidinium organocatalyst.

show abstract

“…Nonetheless, the reactions involving the construction of 1,3-nonadjacent stereogenic centers in a highly stereoselective manner are still scarce, indicating the difficulty in controlling the stereoselectivities of both processes. [2][3][4][5] In addition, the reported reactions are limited to those of highly acidic pronucleophiles because of the inherent weak basicity of chiral organic bases, such as chiral tertiary amines [2] and guanidines, [3] which are commonly used as chiral Brønsted base catalysts in this type of enantioselective reaction. Thus, the construction of 1,3-nonadjacent stereogenic centers with less acidic pronucleophiles, particularly those having pK a values higher than 20 in DMSO (dimethyl sulfoxide), have never been achieved.…”

Section: Introductionmentioning

confidence: 99%

Construction of 1,3‐Nonadjacent Stereogenic Centers Through Enantioselective Addition of α‐Thioacetamides to α‐Substituted Vinyl Sulfones Catalyzed by Chiral Strong Brønsted Base

Kondoh,

Ojima,

Ishikawa

et al. 2023

Advanced Science

Self Cite

View full text Add to dashboard Cite

An enantioselective addition reaction for the construction of 1,3‐nonadjacent stereogenic centers is developed by means of a chiral strong Brønsted base catalyst. The chiral sodium ureate catalyst efficiently promoted the reaction of α‐thioacetamides as less acidic pronucleophiles with vinyl sulfones having a variety of α‐substituents including aryl, alkyl and halo groups, and α‐phenylacrylates, accomplishing the construction of various 1,3‐nonadjacent stereogenic centers in highly diastereo‐ and enantioselective manners. This is a rare example of the construction of 1,3‐nonadjacent stereogenic centers with less acidic pronucleophiles. In addition, the application of Michael acceptors having various types of α‐substituents in a single catalyst system is achieved for the first time, demonstrating the utility of the present catalyst system for the construction of 1,3‐nonadjacent stereogenic centers.

show abstract

Asymmetric Base Organocatalysis

Cited by 4 publications

References 174 publications

Brønsted Base Catalyzed Conjugate Addition of β-Acylvinyl Anion Equivalents to α,β-Unsaturated Ketones

Brønsted Base Catalyzed Conjugate Addition of β-Acylvinyl Anion Equivalents to α,β-Unsaturated Ketones

Exploring Guanidinium Organocatalysts for Hypoiodite‐Mediated Reactions

Construction of 1,3‐Nonadjacent Stereogenic Centers Through Enantioselective Addition of α‐Thioacetamides to α‐Substituted Vinyl Sulfones Catalyzed by Chiral Strong Brønsted Base

Contact Info

Product

Resources

About