Diastereo‐ and Enantioselective 1,4‐Difunctionalization of Borylenynes by Catalytic Conjunctive Cross‐Coupling

Law, Chunyin; Kativhu, Elton; Wang, Johnny; Morken, James P.

doi:10.1002/anie.202001580

“…Finally, we explored the scope of alkyl-derived ate complexes. Primary (32,33), secondary (34), and tertiary ( 35) boronic esters all coupled cleanly and selectively. Coupling products derived from tertiary boronic esters often provided poor conversion to the alcohol (35) during oxidation.…”

Section: Scheme 2 Scope Of Allylic Carbonates a Amentioning

confidence: 99%

Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol

Davis

¹

,

Luvaga

²

,

Ready

³

2021

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Alkenyl boronates add to Ir(π-allyl) intermediates with high enantioselectivity. A 1,2-metalate shift forms a second C−C bond and sets a 1,3-stereochemical relationship. The three-component coupling provides tertiary boronic esters that can undergo multiple additional functionalizations. An extension to trisubstituted olefins sets three contiguous stereocenters.M ulticomponent couplings generate complex molecular architectures from simple substrates. 1−3 Enantioselective variants are particularly valuable, especially when multiple stereocenters are set in a single operation. 4,5 Within the field of multicomponent couplings, organoboronic esters have played a prominent role. 6−12 They are widely available and generally

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“…Morken has since extended this conjunctive cross-coupling to include enyne-derived boronate complexes 74,which give a-hydroxy allenes 75 after oxidative work-up (Scheme 14). [36] Interestingly,e nyne boronates derived from Z-alkenes provided a-boryl allenes with high diastereoselectivity,w hereas E-alkene substrates gave low diastereoselectivity.T his was rationalized based on the steric interactions between the migrating group and the palladium complex:i n the case of the Z-alkene,complex syn-76 has these moieties in close proximity so they orientate to minimize steric interactions,m aking anti-76 the reactive conformer;w hereas in the E substrate,t here is little interaction between the migrating group and the palladium complex in either conformers anti-77 or syn-77,r esulting in poor diastereocontrol. Forreactions with alkyl migrating groups,substitution of the pinacol ligand on boron for an acenaphthoquinone-derived boronic substituent (hac*) was essential for achieving high stereoselectivity,w hich was attributed to enhanced catalystsubstrate steric interactions.…”

Section: Transition Metal-catalyzed Conjunctive Cross-couplingsmentioning

confidence: 99%

Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

Wang

¹

,

Jing

²

,

Noble

³

et al. 2020

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The stereospecific 1,2‐migration of boronate complexes is one of the most representative reactions in boron chemistry. This process has been used extensively to develop powerful methods for asymmetric synthesis, with applications spanning from pharmaceuticals to natural products. Typically, 1,2‐migration of boronate complexes is driven by displacement of an α‐leaving group, oxidation of an α‐boryl radical, or electrophilic activation of an alkenyl boronate complex. The aim of this article is to summarize the recent advances in the rapidly expanding field of electrophile‐induced stereospecific 1,2‐migration of groups from boron to sp2 and sp3 carbon centers. It will be shown that three different conceptual approaches can be utilized to enable the 1,2‐migration of boronate complexes: stereospecific Zweifel‐type reactions, catalytic conjunctive coupling reactions, and transition metal‐free sp2–sp3 couplings. A discussion of the reaction scope, mechanistic insights, and synthetic applications of the work described is also presented.

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“…Morken has since extended this conjunctive cross‐coupling to include enyne‐derived boronate complexes 74 , which give α‐hydroxy allenes 75 after oxidative work‐up (Scheme ) . Interestingly, enyne boronates derived from Z ‐alkenes provided α‐boryl allenes with high diastereoselectivity, whereas E ‐alkene substrates gave low diastereoselectivity.…”

Section: Stereospecific 12‐migration Of Alkenyl Boronates Induced Bymentioning

confidence: 99%

Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

Wang

¹

,

Jing

²

,

Noble

³

et al. 2020

Angewandte Chemie

25

0

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The stereospecific 1,2‐migration of boronate complexes is one of the most representative reactions in boron chemistry. This process has been used extensively to develop powerful methods for asymmetric synthesis, with applications spanning from pharmaceuticals to natural products. Typically, 1,2‐migration of boronate complexes is driven by displacement of an α‐leaving group, oxidation of an α‐boryl radical, or electrophilic activation of an alkenyl boronate complex. The aim of this article is to summarize the recent advances in the rapidly expanding field of electrophile‐induced stereospecific 1,2‐migration of groups from boron to sp2 and sp3 carbon centers. It will be shown that three different conceptual approaches can be utilized to enable the 1,2‐migration of boronate complexes: stereospecific Zweifel‐type reactions, catalytic conjunctive coupling reactions, and transition metal‐free sp2–sp3 couplings. A discussion of the reaction scope, mechanistic insights, and synthetic applications of the work described is also presented.

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Diastereo‐ and Enantioselective 1,4‐Difunctionalization of Borylenynes by Catalytic Conjunctive Cross‐Coupling

Cited by 50 publications

References 78 publications

Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol

Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol

Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

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