Rhodium-Catalyzed Hydroformylation of Cyclopropenes

Sherrill, William M.; Rubin, Michael

doi:10.1021/ja805059f

Cited by 121 publications

(59 citation statements)

References 102 publications

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“…[1,2] To further enhance the synthetic potential of cyclopropenes, the development of expeditious methods for the synthesis of enantioenriched cyclopropenes is highly desirable.[3] In this context, a cyclopropenation reaction of alkynes with diazo compounds that is catalyzed by chiral dirhodium(II) complexes represents one of the most powerful means for the construction of this class of optically active building blocks. Doyle, Müller, and co-workers were the first to demonstrate asymmetric induction (up to !…”

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confidence: 99%

Highly Enantioselective Cyclopropenation Reaction of 1‐Alkynes with α‐Alkyl‐α‐Diazoesters Catalyzed by Dirhodium(II) Carboxylates

Goto¹,

et al. 2011

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As a result of enormous ring strain, cyclopropene compounds display a range of diverse reactivities in both noncatalytic and transition-metal-catalyzed transformations, thus presenting unique opportunities for organic synthesis. [1,2] To further enhance the synthetic potential of cyclopropenes, the development of expeditious methods for the synthesis of enantioenriched cyclopropenes is highly desirable.[3] In this context, a cyclopropenation reaction of alkynes with diazo compounds that is catalyzed by chiral dirhodium(II) complexes represents one of the most powerful means for the construction of this class of optically active building blocks. Doyle, Müller, and co-workers were the first to demonstrate asymmetric induction (up to ! 98 % ee) in cyclopropenation reactions of terminal alkynes including propargyl alcohol or propargylamine derivatives with diazoacetates using [Rh 2 (5S-mepy) 4 ] (2 a; Scheme 1) as a chiral catalyst.[4] Doyle et al. also reported an enantioselective intramolecular cyclopropenation of diazoacetates, in which [Rh 2 (4S-ibaz) 4 ] (2 b) provided macrocyclic cyclopropenes in up to ! 99 % ee.[5] Corey and coworkers demonstrated that a new mixed carboxylate/carboxamidate catalyst [Rh 2 (OAc)(dpti) 3 ] (3) is highly exceptional for cyclopropenation of a broad range of terminal alkynes with ethyl diazoacetate.[6] The extension of this methodology to include a-substituted a-diazoacetates is particularly attractive because it has the capability to form cyclopropenes with a quaternary stereogenic carbon center. [7][8][9] Although high levels of enantioselectivity (up to 99 % ee) in cyclopropenations of terminal alkynes with aryldiazoacetates [7a] or arylvinyldiazoacetates [7b] under catalysis by [Rh 2 (S-dosp) 4 ] (4) have been reported by Davies and co-workers, the goal for the reaction with a-alkyl-a-diazoesters remains elusive because of the propensity to form a,b-unsaturated esters through a 1,2-hydride shift.[10] Panne and Fox recently disclosed that dirhodium(II) tetrapivalate exhibits high selectivity for cyclopropenation over alkene formation in the reaction of terminal alkynes with a-alkyl-a-diazoesters. [11,12] However, to the best of our knowledge, an enantioselective version of this reaction has not been reported.Our research group has previously demonstrated the first examples of highly enantio-, diastereo-, and chemoselective intramolecular C À H insertion reactions of a-alkyl-a-diazoesters by using dirhodium(II) tetrakis[N-phthaloyl-(S)-tertleucinate] ([Rh 2 (S-pttl) 4 ], 1 a) in which high levels of asymmetric induction (up to 95 % ee) were achieved. [13][14][15] Herein, we report that [Rh 2 (S-tbpttl) 4 ] (1 f), a new dirhodium(II) carboxylate complex that incorporates N-tetrabromophthaloyl-(S)-tert-leucinate as chiral bridging ligands, catalyzes the cyclopropenation reaction of terminal alkynes with 2,4-dimethyl-3-pentyl a-alkyl-a-diazoacetates to give 1,2-disubstituted 2-cyclopropenecarboxylates in good to high yields and with up to 99 % ee. Scheme 1. Chiral dirhodium(II) com...

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confidence: 99%

Highly Enantioselective Cyclopropenation Reaction of 1‐Alkynes with α‐Alkyl‐α‐Diazoesters Catalyzed by Dirhodium(II) Carboxylates

Goto¹,

et al. 2011

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“…After screening a variety of commercially available ligands, an asymmetric hydroformylation of prochiral cyclopropenes have also been performed, and enantiomerically enriched cyclopropenes 131 could be obtained in excellent yields and moderate to good enantiomeric excesses (Scheme 27). 95 Most recently, Dong and co-workers reported an enantioselective desymmetrization of cyclopropenes with salicylaldehydes by intermolecular Rh-catalyzed hydroacylation using ferrocene-based phosphines as ligands. Cyclopropylketones, bearing quaternary stereocenters, are produced with diastereocontrol (up to >20 : 1) and excellent enantiomeric excesses (up to > 99 ee).…”

Section: Hydrometalation Reactionsmentioning

confidence: 99%

Recent developments of cyclopropene chemistry

2011

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This critical review discusses recent developments in the field of cyclopropene chemistry. Although several excellent reviews that mainly focused on the thermolysis and pyrolysis as well as metal-mediated reactions of cyclopropenes have been published, significant new developments have also been achieved in recent years. This brand new review provides an overview of the progress from 2007 to 2011 on the syntheses and transformations of cyclopropenes as well as their related mechanistic studies (238 references).

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“…Tortosa and Rubin were able to find chiral copper or rhodium complexes which afforded the corresponding enantioenriched cyclopropanes. 56,58 …”

Section: Introductionmentioning

confidence: 99%