The Rhodium(I)‐Catalyzed Alder‐Ene Reaction

Brummond, Kay M.; McCabe, Jamie M.

doi:10.1002/3527604693.ch8

Cited by 13 publications

(6 citation statements)

References 26 publications

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“…6 Many transition-metal compounds have been used as catalysts in the Alder-ene-type reaction. 7 However, some of the reactions are completely substrate-dependent and metal catalysts show low functional-group compatibility.…”

Section: Equationmentioning

confidence: 99%

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The Gold(I)-Catalyzed Cycloisomerization of 1,6-Enynes to 1,4-Dienes

Lee¹,

Kim²,

Kim³

et al. 2006

Synlett

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Section: Equationmentioning

confidence: 99%

“…The transition-metal-catalyzed formation of 1,4-dienes from 1,6-enynes is an intramolecular Alder-ene reaction. 6 Many transition-metal compounds have been used as catalysts in the Alder-ene-type reaction. 7 However, some of the reactions are completely substrate-dependent and metal catalysts show low functional-group compatibility.…”

Section: Equationmentioning

confidence: 99%

The Gold(I)-Catalyzed Cycloisomerization of 1,6-Enynes to 1,4-Dienes

Lee¹,

Kim²,

Kim³

et al. 2006

Synlett

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“…The rhodium(I)-catalyzed cycloisomerization reaction, 4 firstly published by Zhang, 5 enables a highly effective and enantioselective access to cyclic five-membered-ring systems. 6 The transformation of linear 1,6-enynes proceeds by application of chiral cationic rhodium complexes with enantiomerically pure chelating bisphosphane ligands, preferably BINAP, 7 delivering the corresponding enals with excellent levels of enantioselectivity.…”

Section: Scheme 1 Rhodium-catalyzed Cycloisomerization As An Entry To Sequential Transformationsmentioning

confidence: 99%

Enantioselective One-Pot Rhodium-Catalyzed Cycloisomerization-Wittig Sequence to Chiral Functionalized 4-Alkyl 3-Alkylidene Tetrahydrofuran(on)es

Körber¹,

Röminger²,

Müller³

2010

Synlett

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Alkyl and (hetero)aryl alkyne allyl alcohols can readily be transformed into chiral 4-alkyl 3-alkylidene tetrahydrofurans and tetrahydrofuranones bearing a,b-unsaturated carbonyl side chains in a one-pot fashion via an enantioselective rhodium-catalyzed cycloisomerization-Wittig olefination sequence in good yields (54-86%).Synthetic efficiency represents a main objective within novel methodology and reaction design. The combination of several elementary reaction steps within a one-pot process features great economic and ecological potential as well as a crucial challenge. Naturally, the spotlight is turned on the combination of transformations dealing with exceptionally mild reaction conditions. Above all, transition-metal catalyses take in a predestined role in this context, especially if they can be directed in a domino fashion generating a suitable reactive functionality en route. Among numerous transition-metal-catalyzed cyclizations, cycloisomerization of 1,6-enynes 1 has become an outstanding tool to form cycles bearing a 1,4-diene functionality. In case of alkyne allyl alcohols the cycloisomerization reaction ultimately leads to g,d-enals due to the tautomerism of the elusive dienol intermediate. These resulting enals set the stage for consecutive transformations, for example, conversion of the reactive carbonyl functionality, in a one-pot fashion (Scheme 1).As part of our program to design new transition-metalcatalyzed sequences initiated by intramolecular cycloisomerization, we are particularly interested in sequential one-pot processes. Within our studies we have already established a variety of palladium-and iridium-catalyzed cycloisomerization sequences, 2 notably a Pd-catalyzed cycloisomerization-Wittig olefination sequence. 3 Both the Pd-and the Ir-catalyzed cycloisomerization are limited with respect to the substitution pattern at the alkyne position. Dealing with Pd 2 (dba) 3 ·CHCl 3 as a catalyst precursor, the reaction works very well for TMS-substituted alkyne allyl alcohols whereas the Ir-catalyzed version shows a complementary behavior transforming only arylsubstituted alkyne allyl alcohols. However, as a main drawback both routes just furnish the racemic enal products.Scheme 1 Rhodium-catalyzed cycloisomerization as an entry to sequential transformationsThe rhodium(I)-catalyzed cycloisomerization reaction, 4 firstly published by Zhang, 5 enables a highly effective and enantioselective access to cyclic five-membered-ring systems. 6 The transformation of linear 1,6-enynes proceeds by application of chiral cationic rhodium complexes with enantiomerically pure chelating bisphosphane ligands, preferably BINAP, 7 delivering the corresponding enals with excellent levels of enantioselectivity. The configuration of the newly established stereogenic center was determined by anomalous X-ray crystal diffraction 8 and indirectly by diastereoselective kinetic resolution. 9 Just recently, we have reported on the rhodium-catalyzed cycloisomerization of alkyne allyl alcohols and first examples of subsequent...

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“…Atropos biaryl diphosphines have played a pivotal role in the development of asymmetric catalysis and as a result rightfully belong to the privileged class of ligand/structure . However, even though BINAP has this privileged status and is an excellent ligand for a host of transition metal-catalyzed reactions, it is not superior for all transformations and is often substrate-specific . In such cases the steric and electronic properties have to be modified in order to identify an optimum catalyst, which can involve a nontrivial multistep de novo synthesis .…”

Section: Introductionmentioning

confidence: 99%

Can a Butadiene-Based Architecture Compete with its Biaryl Counterpart in Asymmetric Catalysis? Enantiopure Me-CATPHOS, a Remarkably Efficient Ligand for Asymmetric Hydrogenation

et al. 2009

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The double Diels-Alder cycloaddition between 9-methylanthracene and 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne affords the oxide of the atropos diphosphine, Me-CATPHOS, which has an unusual bicyclic buta-1,3-diene-based architecture. Quantum chemical methods using DTF reveal that the barrier to atropinterconversion in Me-CATPHOS is 130 kJ mol -1 , while the corresponding barrier for its unsubstituted counterpart is only 23 kJ mol -1 , entirely consistent with the former being an atropos diphosphine while the latter belongs to the tropos class of ligand. rac-Me-CATPHOS can be resolved by fractional crystallization of the diastereoisomeric complexes formed with (2R,3R)-(-)-2,3-O-dibenzoyltartaric acid and reduction of the resulting enantiopure oxide, accomplished by silane reduction in xylene at 130 °C, to afford an operationally straightforward, three-step synthesis of an entirely new class of atropos buta-1,3-diene-based diphosphine. Rhodium complexes of enantiopure Me-CATPHOS catalyze the asymmetric hydrogenation of a range of dehydroamino acid derivatives, in some cases giving ee's in excess of 99% and in all cases showing a significant enhancement compared with its BINAP counterpart. Gratifyingly, Rh/(S)-Me-CATPHOS outperforms all existing catalysts for the asymmetric hydrogenation of (E)-β-dehydroamino phosphonates, many of which are based on markedly more expensive biaryl-and ferrocenyl-based diphosphines. Surprisingly, in the case of the dehydroamino acid substrates, (S)-Me-CATPHOS provides product of opposite absolute stereochemistry to that obtained with (S)-BINAP, despite both ligands having an S ax configuration, whereas (S)-Me-CATPHOS exerts (S)-BINAP-like stereoinduction for the hydrogenation of β-enamidophosphonates; both ligands afford product with the same absolute configuration.

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The Rhodium(I)‐Catalyzed Alder‐Ene Reaction

Cited by 13 publications

References 26 publications

The Gold(I)-Catalyzed Cycloisomerization of 1,6-Enynes to 1,4-Dienes

The Gold(I)-Catalyzed Cycloisomerization of 1,6-Enynes to 1,4-Dienes

Enantioselective One-Pot Rhodium-Catalyzed Cycloisomerization-Wittig Sequence to Chiral Functionalized 4-Alkyl 3-Alkylidene Tetrahydrofuran(on)es

Can a Butadiene-Based Architecture Compete with its Biaryl Counterpart in Asymmetric Catalysis? Enantiopure Me-CATPHOS, a Remarkably Efficient Ligand for Asymmetric Hydrogenation

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