In 2019,Bulletin of the Chemical Society of Japan included an article by Tsukamoto, Hirokazu; Kawase, Ayumu; Omura, Hirotaka; Doi, Takayuki. Application of 210169-54-3. The article was titled 《Key Factors for High Diastereo- and Enantioselectivity of Umpolung Cyclizations of Aldehyde-Containing Allylpalladium Intermediates》. The information in the text is summarized as follows:
Two palladium/chiral diphosphine-catalyzed umpolung cyclizations of aldehyde-containing allylic acetates and allenes with arylboronic acid are fully investigated to establish key factors in their high stereoselectivities. Both cyclization reactions afford cis-disubstituted pyrrolidine and THF. These occur in high diastereo- and enantioselectivities through a common cationic (Z)-η1-allylpalladium, toward which a ring strain generated in the cyclization step leading to trans-isomers biases the equilibrium through η3-η1-η3-complex in the former cyclization. Varied diastereoselectivities were observed in the formation of five-membered carbocycles and six-membered heterocycles. These reflect release of a ring strain generated in the cyclization step leading to trans-isomers and a different distribution of the (Z)- and the (E)-η1-allylpalladium intermediates generated by the oxidative addition of allylic acetates to Pd(0) or carbopalladation of allenes, resp. A sterically demanding substituent at the center of the allyl moiety is necessary for high diastereo- and enantioselectivity. The enantioselectivity of the former cyclization was lowered by the presence of organometallic reductants or reagents, possibly causing the formation of neutral η1-allylpalladium species. We used a chiral allylic acetate containing (E)-deuterium-labeled alkene to demonstrate that the electrophilic attack of the aldehyde to the allyl ligand occurred on the side where the palladium existed, consistent with the Zimmerman-Traxler transition state. In the experiment, the researchers used (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3Application of 210169-54-3)
(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) may be used for: regio- and stereoselective preparation of axially chiral arylnaphthalene derivatives via rhodium-catalyzed [2+2+2] cycloaddition of diynes with naphthalenepropynoic acid derivatives or diastereo- and enantioselective hydrogenation of α-amino-β-keto ester hydrochlorides catalyzed by an iridium complex.Application of 210169-54-3
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis