6051-52-1Relevant articles and documents
Photochemical Organocatalytic Regio- and Enantioselective Conjugate Addition of Allyl Groups to Enals
Berger, Martin,Carboni, Davide,Melchiorre, Paolo
supporting information, p. 26373 - 26377 (2021/11/16)
We report the first catalytic enantioselective conjugate addition of allyl groups to α,β-unsaturated aldehydes. The chemistry exploits the visible-light-excitation of chiral iminium ions to activate allyl silanes towards the formation of allylic radicals, which are then intercepted stereoselectively. The underlying radical mechanism of this process overcomes the poor regio- and chemoselectivity that traditionally affects the conjugate allylation of enals proceeding via polar pathways. We also demonstrate how this organocatalytic strategy could selectively install a valuable prenyl fragment at the β-carbon of enals.
[Pd]-Catalyzedpara-selective allylation of phenols: access to 4-[(E)-3-aryl/alkylprop-2-enyl]phenols
Chinnabattigalla, Sreenivasulu,Choudhury, Aditya,Gedu, Satyanarayana
supporting information, p. 8259 - 8263 (2021/10/12)
4-[(E)-3-Arylprop-2-enyl]phenols are omnipresent scaffolds and constitute natural products and biologically significant compounds. Obtusastyrene and obtustyrene are two such phenolic-based natural products isolated fromDalbergia retusa. The development of strategies based on a site-selective allylation, particularly protecting group-free substrates and non-activated coupling agents, is indispensable in organic synthesis. Herein, we present a highly regioselective [Pd]-catalyzedpara-allylation of phenols using simple, inactivated allylic alcohols as allylating coupling partners. Notably, this strategy is successful in open-air and under mild reaction conditions. Besides, the efficacy of the present protocol was demonstrated by the direct synthesis of obtusastyrene and obtustyrene.
Regio- and Enantioselective Preparation of Chiral Allylic Sulfones Featuring Elusive Quaternary Stereocenters
Cai, Aijie,Kleij, Arjan W.
supporting information, p. 14944 - 14949 (2019/11/05)
We describe here the first general asymmetric synthesis of sterically encumbered α,α-disubstituted allylic sulfones via Pd-catalyzed allylic substitution. The design and application of a new and highly efficient phosphoramidite ligand (L10) proved to be crucial, and a wide variety of challenging allylic sulfones featuring quaternary stereocenters could be obtained in good yields and with good to excellent levels of regio- and enantioselectivities under attractive process conditions. The developed methodology employs easily accessible chemical feedstock including racemic allylic precursors and sodium sulfinates. The utility of the method is further demonstrated by the synthesis of the sesquiterpene (?)-Agelasidine A.
