Pd‐Catalyzed Cleavage of Benzylic Nitro Bonds: New Opportunities for Asymmetric Synthesis

Motoyoshi, Hajime; Carreira, Erick M.

doi:10.1002/ange.200604263

Cited by 7 publications

(5 citation statements)

References 88 publications

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“…The viability of the proposal was first assessed for basecatalyzed conjugate addition reactions, by using a selection of prototypical Michael acceptors and gem-bisA C H T U N G T R E N N U N G (sulfone)s 1-5. Because of the easy removal of the sulfonyl group, that is, Mg/MeOH, [7] success in this goal would represent an attractive way for the installation of formal alkyl fragments at the b-position of the carbonyl function. In addition, by proper choice of a chiral non-racemic organic catalyst, the C-C bond-forming process could be rendered enantioselective.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Conjugate Additions of Geminal Bis(sulfone)s: Expanding the Chemistry of Sulfones as Simple Alkyl Anion Equivalents

Landa

Puente

Santos

et al. 2009

Chemistry A European J

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The value of cyclic gem-bis(sulfone) 4 as a simple alkyl nucleophile equivalent in catalytic C-C bond-forming reactions is demonstrated. The 1,4-type nucleophilic additions of bis(sulfone) 4 to alpha,beta-unsaturated ketones take place by assistance of catalytic guanidine base. On the other hand, pyrrolidines are able to catalyze the conjugate addition of 4 to both enones and enals, likely by means of iminium ion activation. Upon exploration of the best chiral pyrrolidine catalyst, it has been found that the addition of 4 to enals catalyzed by diphenylprolinol silyl ether 10 proceeds with very high enantioselectivity (beta-aryl-substituted enals >95% ee; beta-alkyl substituted enals up to 94% ee; ee = enantiomeric excess). Further reductive desulfonation of adducts gives rise to the corresponding beta-methyl aldehydes, as well as the derived alcohols, acetals, and methyl esters after simple (Mg, MeOH) well-established protocols. Application of the procedure to the synthesis of biologically relevant phenethyl building blocks is shown. Most interestingly, alpha-alkylation of initially obtained bis(sulfone) adducts can be done even with less reactive alkylating reagents, such as long linear-chain or branched-chain alkyl halides. Accordingly, upon the desulfonation process, a general, experimentally simple and highly enantioselective access to beta-branched aldehydes, alcohols, or esters is possible. Further exploration of the method includes the use of chiral alpha,beta-unsaturated aldehydes derived from citronellal as the Michael acceptor partners. In these instances, the sense of the conjugate addition of 4 is controlled by the chirality of the pyrrolidine catalyst, thus allowing for a stereochemically predictable access to 1,3-dimethyl arrays, such as those present in deoxygenated polyketide-type natural products. The intramolecular variation of this technology by using doubly unsaturated aldehyde-ester 22 illustrated the site selectivity of the procedure and its potential for tandem processes leading to highly substituted polycyclic systems, such as 24.

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Section: Resultsmentioning

confidence: 99%

Catalytic Conjugate Additions of Geminal Bis(sulfone)s: Expanding the Chemistry of Sulfones as Simple Alkyl Anion Equivalents

Landa

Puente

Santos

et al. 2009

Chemistry A European J

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“…Their reports were followed by the work of Carreira, who demonstrated that palladium‐catalysed hydrogenation was also feasible on secondary benzylic nitro substrates in 2007 ( 328 , Figure 12). [8] …”

Section: Transition Metal‐promoted Processesmentioning

confidence: 99%

“… Recent examples of transition metal promoted protodenitration of nitroalkanes by Maier (1984), [254] Vankar (1991), [255] Desmaële (2001), [256] Tyman (2006), [257] Carreira (2007), [8] Rutjes (2009), [258] Johnston (2010), [259] Kozlowski (2013), [260] Taratayko (2013), [261] Seidel (2015), [262] Yuan (2015), [263] Samanta (2016), [264] Singh (2017), [265] Romney (2019), [266] Seidel (2020) [217] . * Protodenitration was accompanied by desulfurization .…”

Section: Transition Metal‐promoted Processesmentioning

confidence: 99%

“…The need for this essential transformation was explicitly highlighted by two prominent chemists in different eras of organic synthesis, namely by Kornblum [7] and, more recently, by Carreira [8] . As early as 1978, Kornblum stated, “ With such a wide variety of unusual structures readily available it is apparent that any process which results in the replacement of a nitro group by other atoms or groups of atoms has considerable value .” [7] Although substrate‐specific examples of protodenitration had appeared scattered since the dawn of the 20th century, a general method for this crucial transformation remained elusive until the seventies.…”

Section: Introductionmentioning

confidence: 99%

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The Last Fortress of Tin's Tyranny – Protodenitration of Nitroalkanes

et al. 2023

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Protodenitration, a direct reduction of nitroalkanes to corresponding alkanes, already spans two centuries and is enabled by various reagents. This mini-review provides a historical development of the fundamental transformation and highlights the governing position of the Ono-Tanner reaction employing tributyltin hydride. Due to the unchallenged dominance of the toxic tributyltin hydride and environmentally unpopular solvents sharply contrasting with modern ecological trends, the current situation was dubbed "the last fortress of tin's tyranny."[a

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“…However, the large number of synthetic transformation this function is involved with, has greatly aided the nitro group chemistry to remain in the spotlight [4][5][6]. Among these transformations, reduction of the nitro to amino group is of fundamental importance since it represents a gate to primary amines and other nitrogen containing compounds.…”

Section: Introductionmentioning

confidence: 98%

Nitroalkanes as Key Compounds for the Synthesis of Amino Derivatives

Ballini¹,

Gabrielli²,

Palmieri³

et al. 2011

COC

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The carbanion stabilizing effect of the nitro group makes nitroalkanes ideal reagents in carbon-carbon bond formation. Once introduced in a molecular framework, the nitro group is amenable to further transformations including reduction to primary amines. The aim of this review is to explore the utilization of nitroalkanes as effective substrates for the preparation of important target compounds featured by the amino group. These will include simple primary amines, diamines, amino acids, piperidines, pyrrolidines and heteroaromatic derivatives. A particular emphasis will be placed on the synthesis of enantioenriched amino derivatives mediated by organocatalysts or organometallic complexes.

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Pd‐Catalyzed Cleavage of Benzylic Nitro Bonds: New Opportunities for Asymmetric Synthesis

Cited by 7 publications

References 88 publications

Catalytic Conjugate Additions of Geminal Bis(sulfone)s: Expanding the Chemistry of Sulfones as Simple Alkyl Anion Equivalents

Catalytic Conjugate Additions of Geminal Bis(sulfone)s: Expanding the Chemistry of Sulfones as Simple Alkyl Anion Equivalents

The Last Fortress of Tin's Tyranny – Protodenitration of Nitroalkanes

Nitroalkanes as Key Compounds for the Synthesis of Amino Derivatives

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