Asymmetric palladium(0)-mediated synthesis of 2-vinylchroman

Metal‐Catalyzed Enantioselective Allylation in Asymmetric Synthesis

“…[215] However, the highly enantioselective intramolecular asymmetric allylic substitution of 5-(2'-hydroxyaryl)-2(E)-pentenylmethyl carbonates 186 for the synthesis of chiral chromans R-187 was successfully demonstrated by Trost et al When the ligand (R,R)-L130 was used, the configuration of the double bond in the substrates was found to have a profound impact on the enantioselectivity and the absolute configuration of the chiral chroman products. In all the cases shown in the first two equations of Scheme 65, trisubstituted Z alkenes gave the highest ee values (95-97 %) among all the substrates with R = Me, and significantly higher than their E isomers.…”

Palladium-catalysed reactions of alcohols. Part B: Formation of C–C and C–N bonds from unsaturated alcohols

“…5 and 6), [18][19][20][21][22] they have been mostly performed using stoichiometric amounts of ammonium halides in organic solvents (Table 1, entry 4; Eq. 7) [23][24][25][26][27][28][29][30][31][32][33][34][35] or catalytic amounts of n-Bu 4 NCl in water (Table 1, entry 5; Eq. 8).…”

Palladium‐Catalyzed Formation of Cyclic Ethers – Regio‐, Stereo‐ and Enantioselectivity of the Reaction

“…[19] This cyclization has also been achieved in an enantioselective way in the presence of chiral ligands. [15,[20][21][22][23][24][25] The Pd II -catalyzed cyclization of alkenyl alcohols has led to cyclic enols by a β-hydride elimination, or to oxygen heterocycles bearing a vinyl group through a β-hydroxy elimination, if the alkenol possesses an allyl alcohol moiety. [2,3,5] A large variety of oxygen-containing heterocycles have been obtained with this methodology, [26][27][28][29][30][31][32][33][34] even in an asymmetric fashion.…”