Highly regioselective and diastereodivergent aminomethylative annulation of dienyl alcohols enabled by a hydrogen-bonding assisting effect

Abstract

A ligand-controlled palladium-catalyzed highly regioselective and diastereodivergent aminomethylative annulation of dienyl alcohols with aminals has been established, which allows for producing either cis- or trans-disubstituted isochromans in good yields with...

Asymmetric cascades of the π-allyl complex: a journey from transition-metal catalysis to metallaphotocatalysis

“…The developed method involved the reaction of dienetethered alcohols 47a with diamines 47b in the presence of 5 mol% of [Pd(allyl)Cl] 2 along with 12 mol% of BINOL-derived chiral phosphoramidite ligand to furnish optically active transdisubstituted isochromans 47c in good to excellent yield (Scheme 47). 79 However, the enantioselectivity was found to be moderate. The proposed catalytic cycle relied upon the [1,4]oxazines.…”

Recent advances in Pd-catalyzed asymmetric cyclization reactions

“…Recently, Huang and Liu reported an enantioselective aminomethylative annulation reaction between dienyl alcohols 95 and aminals 96 to provide a straightforward way to access various chiral cis-disubstituted isochromans 97 with moderate to good enantioselectivities (Scheme 20). 49 VCPs could serve as three-or five-carbon synthons depending on whether the vinyl substituent participates in the cycloaddition. The development of cycloaddition and related addition reactions involving VCPs was reviewed by Tang, Li and coworkers in 2020.…”

“…Recently, Huang and Liu reported an enantioselective aminomethylative annulation reaction between dienyl alcohols 95 and aminals 96 to provide a straightforward way to access various chiral cis -disubstituted isochromans 97 with moderate to good enantioselectivities (Scheme 20). 49 Notably, the hydroxyl group of dienyl alcohols 95 was essential for facilitating the Pd-catalyzed Heck insertion regioselectively to generate the π-allylpalladium intermediate Int-II through hydrogen-bonding between the hydroxyl group and aminal moiety in intermediate Int-I . It was found that owing to the strong π-accepting ability of the chiral phosphinamide ligand, the palladium center could coordinate with the alcohol in intermediate Int-II , followed by inner-sphere reductive elimination to produce the cis -diastereoselective product.…”

Asymmetric Hydroxymethylative Etherification of 1,3-Dienes with Isatins and Alcohols via Pd(0)-π-Lewis Base Catalysis

“…In 2021, Huang documented a rare strategy for enantioselective aminomethylative etherification of 1,3-dienes by using in situ generated aminomethyl cyclopalladated complexes from N , O -acetals and aliphatic alcohols, affording valuable chiral 1,3-aminol ethers, albeit with a single stereogenic center (Scheme b) . As a result, the development of a modular and mechanistically distinct strategy for concurrently introducing an alkoxyl group and another chiral moiety into 1,3-dienes is highly desirable, which could significantly enrich the structural and stereochemical diversity and complexity.…”