Design of Chiral Bis-phosphoric Acid Catalyst Derived from (R)-3,3′-Di(2-hydroxy-3-arylphenyl)binaphthol: Catalytic Enantioselective Diels–Alder Reaction of α,β-Unsaturated Aldehydes with Amidodienes

Abstract

Chiral bis-phosphoric acid 1 was designed to identify a new class of structural features in chiral Brønsted acid catalysts. X-ray diffraction analysis revealed the single atropisomer 1, bearing S axial chirality at 3,3'-biaryl substituents on (R)-binaphthyl and intramolecular hydrogen bonding between the two phosphoric acid moieties. The newly designed bis-phosphoric acid 1 was evaluated in the Diels-Alder reaction of α,β-unsaturated aldehydes 4 with 1-N-acylamino-1,3-butadienes 3. After systematic variation of the catalyst substituents, as well as the N-acyl substituents of 1,3-butadiene, the use of an N-Cbz amidodiene 3a in the presence of bis-phosphoric acid 1e with a 2,4,6-tri-isopropylphenyl group was found to be optimal to yield the 1S,6R enantiomeric product 5aa in a Diels-Alder reaction of acrolein (4a). Application of this method to substituted substrates was found to be an efficient approach to the enantioselective synthesis of 3- and 3,6-substituted cyclic formylcarbamates 5. The specific character as well as the utility of 1e was further established by comparing its enantioselectivity, absolute stereochemistry, and catalytic efficiency with those of mono-phosphoric acid 2.

Dual Brønsted‐acid Organocatalysis: Cooperative Asymmetric Catalysis with Combined Phosphoric and Carboxylic Acids

“…[31,36] The higher yield (79 %v s. 36 %) suggests that the presence of an additional phosphoric acid significantly increases theB rønsted-acidity, while the observed inverted stereoselectivity (99 %v s. À88 % ee for the (1S,6R)-product 18 a)p oints at an entirely different structure of the stereodetermining transition state. In the initial investigation,t he superior activity and selectivity of the symmetric triisopropylphenyl-substituted catalyst( R)-11 a wasd emonstrated in comparison to the TRIPm onophosphoric acid ((R)-10 b,s ee Scheme 8a nd Ta ble 1e ntries 1-2).…”

“…In the initial investigation,t he superior activity and selectivity of the symmetric triisopropylphenyl-substituted catalyst( R)-11 a wasd emonstrated in comparison to the TRIPm onophosphoric acid ((R)-10 b,s ee Scheme 8a nd Ta ble 1e ntries 1-2). [31,36] The higher yield (79 %v s. 36 %) suggests that the presence of an additional phosphoric acid significantly increases theB rønsted-acidity, while the observed inverted stereoselectivity (99 %v s. À88 % ee for the (1S,6R)-product 18 a)p oints at an entirely different structure of the stereodetermining transition state.…”

“…Following this design principle, Te rada's group developed the C 2 -symmetric bisphosphoric acids 11 [31] and their unsymmetric counterparts 12, [32] featuring different aryl-substituents. More recently,t he heterofunctional phosphoric acid-carboxylic acid catalyst 13 was developed (see Scheme7).…”

A Doubly Axially Chiral Phosphoric Acid Catalyst for the Asymmetric Tandem Oxyfluorination of Enamides

“…Recent elegant progress has been disclosed with the aim of diversifying available chiral phosphoric acid scaffolds. [20] A novel catalyst architecture able to effectively emulate TRIP, while at the same time providing new opportunities for catalyst modification is an exciting proposition. Accordingly, we found that PhDAP catalyzes the formation of cyclic aminals with selectivities comparable to those reported using BINOL-derived phosphoric acids [Eq.…”

Recent Advances in the Use of Chiral Brønsted Acids as Cooperative Catalysts in Cascade and Multicomponent Reactions

“…[3] The independent research of Akiyama et al as well as Uraguchi and Terada made 1,1'-bi-2-naphthol (BINOL) phosphoric acids fashionable as asymmetric catalysis in 2004. [4] Since then, other novel BINOL-based organic acids have been developed, such as N-triflyl phosphoramides, [5] dicarboxylic acids, [6] disulfonic acids, [7] chiral sulfonimides, [8] and chiral bis-phosphoric acids, [9] with the intention of expanding the scope of substrates and finding new reaction patterns (Scheme 1).…”