Enantioselective construction of all-carbon quaternary spirocenters through a Pd-catalyzed asymmetric intramolecular ipso-Friedel–Crafts allylic alkylation of phenols

Catalytic Asymmetric Dearomatization by Transition-Metal Catalysis: A Method for Transformations of Aromatic Compounds

“…Their subsequent studies confirmed that Trost ligand (R,R)-L1 is optimal for this reaction, and several para-substituted phenol derivatives could be transformed to their corresponding spiro [4.5]cyclohexadienones in reasonable yields and diastereo-and enantioselectivity. 41 In parallel with the first report from the Hamada group, 40 our group published a general protocol for the synthesis of chiral spiro cyclohexadienones by Ir-catalyzed intramolecular asymmetric allylic dearomatization of para-substituted phenol derivatives (Scheme 11). For an array of nitrogen-or carbon-tethered substrates 45, the desired products 46 could be generated in up to 95% yield with 97% ee under optimized conditions.…”

Katalytische asymmetrische Desaromatisierungen

“…Durch diese Pionierarbeiten angeregt, [47,48,50] [53] Schema 24. Ir-katalysierte asymmetrische allylische Desaromatisierung von Indolen, Phenolen und Pyrrolen nach You et al [51] .…”

Enantioselective Dearomatization of Naphthol Derivatives with Allylic Alcohols by Cooperative Iridium and Brønsted Acid Catalysis

“…[9] Av ariety of highly regio-and enantioselective allylic substitution reactions have been realized with various activated precursors of p-allyl fragments (allyl halides,e sters,a nd carbonates,e tc.) [12] However,t he electrophiles involved in all cases were allyl carbonates.Because of the high synthetic step economy and positive environmental impact (water as the only stoichiometric by-product), the use of synthetically reliable alcohols instead of allyl carbonates in AAA reactions have become more and more popular. [10,11] Very recently,t he groups of You and Hamada independently reported the inter-a nd intra-molecular asymmetric allylic dearomatization (AADA) of naphthols with allyl carbonates,a nd the desired b-naphthalenones were obtained in good yields with excellent chemoand enantioselectivities (Scheme 1a).…”

“…Inspired by these results,aseries of chiral phosphoric acids were tested. could effectively improve the yield to greater than 60 %a nd enantioselectivity to greater than 87 %(entries [11][12][13]. (R)-PA2,( R)-PA4,a nd (R)-PA7 could also promote the reaction (entries 5, 7, and 10), and (R)-PA7 gave the best results with regard to both chemo-and enantioselectivity.…”