Oisaki, Kounosuke published the artcileCatalytic Enantioselective Alkylative Aldol Reaction: Efficient Multicomponent Assembly of Dialkylzincs, Allenic Esters, and Ketones toward Highly Functionalized δ-Lactones with Tetrasubstituted Chiral Centers, COA of Formula: C38H24F4O4P2, the publication is Journal of the American Chemical Society (2007), 129(23), 7439-7443, database is CAplus and MEDLINE.
A general catalytic asym. alkylative aldol reaction is described as a new entry to the catalytic asym. multicomponent reaction (CAMCR). Highly functionalized δ-lactones I (R1 = Me2CHCH2, H2C:CHCH2CH2, Ph, cyclohexyl, 1-cyclohexenyl, 4-BrC6H4, 4-MeOC6H4, R2 = Me; R1R2 = 1,2,3,4-tetrahydronaphthalene-1,1-diyl; R3 = Me, Et, Me2CH, n-Bu) were produced in the presence of a catalytic amount of the Cu(OAc)2-DIFLUORPHOS complex through three-component assembly of dialkylzincs R32Zn, allenic ester H2C:CHCO2Et, and unactivated ketones R1COR2. This CAMCR constructs two C-C bonds and one tetrasubstituted chiral center simultaneously. Conjugate addition of alkylcopper species to an allenic ester produced highly active copper enolate in situ, and the successive asym. aldol addition to ketones followed by lactonization afforded the desired products. The addition of 4A mol. sieves and a Lewis base (Ph2S:O, DMSO, or HMPA) is important for obtaining a high yield, with suppression of the undesired α-addition pathway. Control/crossover experiments suggest that the addition of a Lewis base facilitated the retro-aldol reaction of the α-adducts (proofreading effect). The ketone and copper enolate generated through the retro-aldol reaction were converted to the desired lactone through the γ-aldol pathway, which was trapped by irreversible lactone formation.
Journal of the American Chemical Society published new progress about 503538-69-0. 503538-69-0 belongs to dioxole, auxiliary class (Atropisomeric Bisphosphine Ligands, name is (R)-5,5′-Bis(diphenylphosphino)-2,2,2′,2′-tetrafluoro-4,4′-bi-1,3-benzodioxole, and the molecular formula is C38H24F4O4P2, COA of Formula: C38H24F4O4P2.
Referemce:
https://en.wikipedia.org/wiki/1,3-Benzodioxole,
Dioxole | C3H4O2 – PubChem