Morpholine Ketene Aminal as Amide Enolate Surrogate in Iridium‐Catalyzed Asymmetric Allylic Alkylation

Abstract

Morpholine ketene aminal is employed in iridiumcatalyzedasymmetric allylic alkylation reactions as asurrogate for amide enolates to prepare g,d-unsaturated b-substituted morpholine amides.Kinetic resolution or,alternatively,stereospecific substitution affords the corresponding products in high enantiomeric excess.T he utility of the products generated by this method has been showcased by their further elaboration into amines,k etones,o ra cyl silanes.Ap utative catalytic intermediate (h 3 -allyl)iridium(III) with achiral P, Olefin-ligand was synthetized and characterized for the first time.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Nickel-catalyzed enantioselective vinylation of aryl 2-azaallyl anions

“…4,5 Enantioenriched allylic amines, however, are oen difficult to synthesize using asymmetric catalysis. 6,7 In recent years, practical synthetic routes toward enantioenriched amines have been advanced by Ellman, [8][9][10] Carreira [11][12][13][14][15] and others. [16][17][18][19][20][21] Enantioenriched allylic amines are desirable targets because of their utility, and several methods have been reported that involve the asymmetric addition of organometallic reagents to activated imines in the presence of enantioenriched catalysts.…”

Chirality memory of α-methylene-π-allyl iridium species

“… 1 In addition to enolate chemistry, 2 some examples of transition-metal catalyzed stereospecific functionalizations of optically active allylic derivatives have been recorded. 3 However, reports on the memory of chirality of α-alkylidene-π-allyl metallic species are very limited: the rapid racemization of such chiral intermediate via σ–π–σ-rearrangements has been reported by Tsukamoto ( Scheme 1a ). 4 Herein, we wish to report the observation of an excellent memory of chirality (MOC) in the highly stereoselective reaction of optically active allenylic methyl carbonates with amines affording 2,3-allenylic amines in high ee via α-alkylidene-π-allyl iridium species ( Scheme 1b ).…”

Iridium-Catalyzed Enantioselective α-Allylic Alkylation of Amides Using Vinyl Azide as Amide Enolate Surrogate

“…However, the use of the enantioselective α-allylic alkylation of α-unsubstituted acetamides as a synthetic tool continued to elude our grasp. In 2019, Carreira and coworkers came up with an ingenious solution to this problem by using morpholine ketene aminal as the amide enolate equivalent to develop the first catalytic enantioselective formal allylic alkylation of α-unsubstituted acetamides (Scheme B) . Using branched allylic carbonates as the allylic electrophile, this reaction proceeds with kinetic resolution and gives rise to α-allyl tertiary amides with excellent enantioselectivity.…”