5.32 Hydrovinylation Reactions in Organic Synthesis

RajanBabu, T. V.; Cox, G. Adam; Lim, Hae Ja; Nomura, Nobuyoshi; Sharma, Rakesh Kumar; Smith, Craig R.; Zhang, A.

doi:10.1016/b978-0-08-097742-3.00533-4

Cited by 20 publications

(21 citation statements)

References 150 publications

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“…Heterodimerization reactions involving ethylene and other alkenes catalysed by late transition metals including iron, 1 – 3 cobalt, 4 – 8 nickel, 9 – 13 rhodium, 14 palladium 15 and ruthenium 14a , 16 had a long history 17 even before the more recent discoveries of applications of related chemistry in olefin polymerization reactions emerged. 18 – 21 Among these, palladium, 15 nickel and cobalt, and to a limited extent, ruthenium catalysed reactions 22 – 29 have attracted the most attention in the stereoselective synthesis of small molecules.…”

Section: Introductionmentioning

confidence: 99%

Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes

2015

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Section: Introductionmentioning

confidence: 99%

Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes

2015

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“…The power of the asymmetric hydrovinylation to overcome the inherent stereochemical preference of a substrate will be tested in this reaction. We hoped that the highly tunable phosphoramidite and other ligands (Figure 2) we developed 20b,25 would help address this issue. Moving forward, there was some uncertainty about how we might install the C 4 configuration, even though earlier we had shown in model systems (Scheme 1, b and c) hydroboration followed by catalytic heterogeneous (Pd/C) or homogeneous Ir-catalyzed directed hydrogenation using Crabtree’s catalyst 26 would result in high diastereoselectivity at the ring carbon in some model systems.…”

Section: Resultsmentioning

confidence: 99%

“…Even though we have had extensive experience with asymmetric hydrovinylation reactions including that of 4-methoxystyrene 20b it became apparent that further optimization of the ligand system would be needed as we looked at even more electron-rich styrenes. For example, we found that 2,3-dimethoxy-4-methylstyrene ( 23 ), a key precursor for several diterpenes targets, while giving excellent yields, gave enantioselectivity of only ~ 90% ee under the standard conditions using the original Feringa ligand, L1 .…”

Section: Resultsmentioning

confidence: 99%

“…Even though several creative solutions to tackle this so-called “exocyclic stereochemistry” problem have been advanced, broadly applicable methods that use easily accessible precursors are still needed . We believe that the asymmetric hydrovinylation (AHV) of vinylarenes (Scheme a) and of 1,3-dienes (Scheme b,c) provides an especially attractive opportunity to fill this gap in the synthesis of serrulatanes and amphilectanes, and here we document the full details of our work in the area. In addition to the enantioselective total or formal syntheses of several natural products, we describe how reagent control maybe exercised for the preparation of selected congeners with high diastereoselectivity…”

Section: Introductionmentioning

confidence: 99%

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Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control

et al. 2018

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A stereogenic center, placed at an exocyclic location next to a chiral carbon in a ring to which it is attached, is a ubiquitous structural motif seen in many bioactive natural products including di- and tri-terpenes and steroids. Installation of these centers has been a long-standing problem in organic chemistry. Few classes of compounds illustrate this problem better than serrulatanes and amphilectanes, which carry multiple methyl-bearing exocyclic chiral centers. Nickel-catalyzed asymmetric hydrovinylation (HV) of vinylarenes and 1,3-dienes such as 1-vinylcycloalkenes provide an exceptionally facile way of introducing these chiral centers. This manuscript documents our efforts to demonstrate the generality of the asymmetric HV to access not only the natural products, but also their various diastereoisomeric derivatives. Key to success here is the availability of highly tunable phosphoramidite Ni(II)-complexes useful for overcoming the inherent selectivity of the chiral intermediates. The yields for HV reactions are excellent, and selectivities are in the range of 92–99% for the desired isomers. Discovery of novel, configurationally fluxional, yet sterically less demanding, 2,2′-biphenol-derived phosphoramidite Ni-complexes (fully characterized by X-ray) turned out to be critical for success in several HV reactions. We also report, a less spectacular, yet equally important role of solvents in a metal-ammonia reduction for the installation of a key benzylic chiral center. Starting with simple oxygenated styrene derivatives we iteratively install the various exocyclic chiral centers present in typical serrulatane [e.g., a (+)-p-benzoquinone natural product, elisabethadione, nor-elisabethadione, helioporin D, a known advanced intermediate for the synthesis of colombiasin and elisapterosin] and amphilectane [e.g., A–F, G–J and K,L- pseudopterosins] derivatives. Our attempts to synthesize a hither-to elusive target, elisabethin A, led to a stereoselective, biomimetic route to pseudopterosin A–F aglycone.

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“…Acyclic 1,3-dienes and aldehydes are among the most readily available precursors for organic synthesis, many of them marketed in bulk as feedstock materials for chemical industry . Regio- and enantioselective union of easily accessible 1,3-dienes and aldehydes (industrially produced by alkene hydroformylation) is a reaction whose full potential has not yet been realized and, like other similar reactions of dienes, can provide valuable building blocks adorned with latent functionalities for further synthetic elaboration. − Unlike reactions of simple alkenes, reactions of prochiral dienes present additional challenges, since a multitude of primary products can be formed, even for the simplest of these compounds, such as a monosubstituted ( E )-1,3-diene (Figure A, 1 , R 1 = R 2 = R 3 = H; R 4 = alkyl). Thus, in a generic hydrofunctionalization reaction, possibility exists for the formation of 1,2/2,1-, 1,4/4,1-, and 3,4/4,3-adducts (regioselectivity defined by the number of the carbons of the diene to which are attached the X and H, respectively), in addition to geometrical isomers of the residual double bonds in some of the products, even if an enantioselective reaction can be accomplished.…”

Section: Introductionmentioning

confidence: 99%

α- and β-Functionalized Ketones from 1,3-Dienes and Aldehydes: Control of Regio- and Enantioselectivity in Hydroacylation of 1,3-Dienes

Parsutkar

RajanBabu

2021

J. Am. Chem. Soc.

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Ketones are among the most widely used intermediates in organic synthesis, and their synthesis from inexpensive feedstocks could be quite impactful. Regio-and enantioselective hydroacylation reactions of dienes provide facile entry into useful ketone-bearing chiral motifs with an additional latent functionality (alkene) suitable for further elaboration. Three classes of dienes, 2-or 4-monosubstituted and 2,4-disubstituted 1,3-dienes, undergo cobalt(I)-catalyzed regio-and enantioselective hydroacylation, giving products with high enantiomeric ratios (er). These reactions are highly dependent on the ligands, and we have identified the most useful ligands and reaction conditions for each class of dienes. 2-Substituted and 2,4-disubstituted dienes predominantly undergo 1,2-addition, whereas 4-substituted terminal dienes give highly enantioselective 4,1-or 4,3-hydroacylation depending on the aldehyde, aliphatic aldehydes giving 4,1-addition and aromatic aldehydes giving 4,3-addition. Included among the substrates are feedstock dienes, isoprene (US$1.4/kg) and myrcene (US$129/kg), and several common aldehydes. We propose an oxidative dimerization mechanism that involves a Co(I)/Co(III) redox cycle that appears to be initiated by a cationic Co(I) intermediate. Studies of reactions using isolated neutral and cationic Co(I) complexes confirm the critical role of the cationic intermediates in these reactions. Enantioselective 1,2-hydroacylation of 2-trimethylsiloxy-1,3-diene reveals a hitherto undisclosed route to chiral siloxy-protected aldols. Finally, facile syntheses of the anti-inflammatory drug (S)-Flobufen (2 steps, 92% yield, >99:1 er) and the food additive (S)-Dihydrotagetone (1 step, 83% yield; 96:4 er) from isoprene illustrate the power of this method for the preparation of commercially relevant compounds.

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5.32 Hydrovinylation Reactions in Organic Synthesis

Cited by 20 publications

References 150 publications

Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes

Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes

Broadly Applicable Stereoselective Syntheses of Serrulatane, Amphilectane Diterpenes, and Their Diastereoisomeric Congeners Using Asymmetric Hydrovinylation for Absolute Stereochemical Control

α- and β-Functionalized Ketones from 1,3-Dienes and Aldehydes: Control of Regio- and Enantioselectivity in Hydroacylation of 1,3-Dienes

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