Enantioselective Total Synthesis of (−)‐Martinellic Acid

Pappoppula, Mukesh; Aponick, Aaron

doi:10.1002/anie.201507849

Cited by 42 publications

(25 citation statements)

References 56 publications

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“…With the goal of developing a method to couple these alkyne reactivities in an efficient one‐pot transformation, it was recognized that both reaction and ligand selection would be crucial, and although chiral ligands are most commonly used for enantioselectivity, they can also efficiently control other types of selectivity . Studies from our laboratory have been directed at using heterocyclic chiral biaryl ligands in enantioselective transformations and we postulated that our Stack ligands might also control other types of selectivity. We recently reported conjugate addition to Meldrum's acid derivatives in water, and we decided that this would be a suitable reaction platform from which to build a subsequent catalytic transformation to form the six‐membered lactone 7 .…”

Section: Methodsmentioning

confidence: 99%

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Mishra

Aponick

2019

Angewandte Chemie

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In this work, we report enantioselective orthogonal tandem catalysis for the one pot conversion of Meldrum's acid derivatives and alkynes into δ‐lactones. This new transformation, which resembles a formal [4+2] cycloaddition with concomitant decarboxylation and loss of acetone, proceeds in high yields and excellent enantioselectivity (up to 99 % ee) over a broad substrate scope. The products are densely functionalized and ripe for further transformations, as demonstrated here by both ring‐opening reactions and reduction to saturated lactones. It was discovered that a new and serendipitously formed AgI‐Me‐StackPhos complex efficiently catalyzes the highly selective 6‐endo‐dig cyclization, completely reversing the regiochemistry that has been previously reported in related systems. More generally, in this study we identify a pair of compatible catalysts for alkyne difunctionalization that operate concurrently, which enable the alkyne to act as both a nucleophile and an electrophile in sequential one‐pot transformations.

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Section: Methodsmentioning

confidence: 99%

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Mishra

Aponick

2019

Angewandte Chemie

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“…[156] In 2015, an asymmetric total synthesis of (À )-martinellic acid was achieved and reported by Aponick and co-workers. [157] The key step of their strategy was an asymmetric Cu-catalyzed alkynylation by imidazole-biaryl nitrogen and phosphor chiral axially chiral ligand Stack Phos. [158] In their approach, the total synthesis of (À )-martinellic acid (226) was started from benzocaine to provide allylic carbonate 221 in three steps.…”

Section: Cu (I) Complexesmentioning

confidence: 99%

Catalytic Function of Cu (I) and Cu (II) in Total Synthesis of Alkaloids

et al. 2021

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Recently, Cu-catalyzed carbon-carbon and carbon (sp 2 )-nitrogen bond formation have attracted much attention. Nowadays, they are widely being applied to the total synthesis of an extensive assortment of natural products with complex structures. Natural products chemistry is a discrete part of chemical research, which has been significant in the history of chemistry, the sourcing of substances in early preclinical drug discovery research, pharmacology and discovery of folk medicine. Alkaloids are a class of natural product that contains at least one nitrogen atom. They have diverse and important physiological effects on humans and other animals. In fact, as many as one-quarter of higher plants are estimated to contain alkaloids, of which several thousand (approximately 12000) different types have so far been identified. In this review, we try underscore the total synthesis of naturally occurring alkaloids in which Cu-promoted reaction is at least one of the vital step. Indeed, in this comprehensive review, the impact of Cu-catalyzed cross-coupling reactions in the total synthesis of natural products with a prominence on the evolution of strategies due to copper catalysis will be generally surveyed.

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“…[11] Another quite interesting approach to enantioenriched tetrahydroquinolines employed hydrogenation promoted by metal complexes. [12] It is also worth mentioning the excellent results reported by Aponick [13] in the alkynylation of activated quinolines promoted by phosphine ligands.…”

Section: Introductionmentioning

confidence: 99%

Organocatalytic Stereoselective Addition of Aldehydes to Acylquinolinium Ions

2016

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A direct and simple activation of quinolines, without isolating unstable intermediates, or using isolated N,O‐acetals in the presence of Lewis or Brønsted acids, is described. The procedure is quite straightforward and allows the addition in a stereoselective manner of different aldehydes to various differently substituted quinolines. The desired products were obtained in 28–76 % yields, with dr values up to 83:17 in favor of the syn isomer, and up to 99 % ee. Studies towards the use of acetaldehyde were also performed with different catalysts and the addition was promoted affording the desired product in 62 % yield with 46 % ee. Finally, deprotection and chemical transformations of the enantioenriched adducts were performed.

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Enantioselective Total Synthesis of (−)‐Martinellic Acid

Cited by 42 publications

References 56 publications

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Catalytic Function of Cu (I) and Cu (II) in Total Synthesis of Alkaloids

Organocatalytic Stereoselective Addition of Aldehydes to Acylquinolinium Ions

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