Enantioselective rhodium-catalyzed hydrogenation of enol carbamates in the presence of monodentate phosphines

Enthaler, Stephan; Erre, Giulia; Junge, Kathrin; Michalik, Dirk; Spannenberg, Anke; Marras, Fabrizio; Gladiali, Serafino; Beller, Matthias

doi:10.1016/j.tetasy.2007.06.001

Cited by 37 publications

(21 citation statements)

References 65 publications

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“…The substitution was highly stereoselective, because only single diastereomers were obtained. The synthesis of compound 33b was also reported by us via the phosphine oxide and similar deprotonation/alkylation protocol [37]. The observed stereochemistry was identical and again only one diastereomer is formed.…”

Section: Design and Synthesis Of Chiral Monophosphinessupporting

confidence: 62%

“…More recently, we carried out an enantioselective reduction of enol carbamates, which is an alternative approach to chiral benzylic alcohols [37]. Pioneering work in the field of asymmetric hydrogenation of enol carbamates was reported by Feringa, de Vries, Minnaard and co-workers who obtained enantioselectivities up to 98% ee with rhodium-catalysts containing monodentate phosphoramidites (MonoPhos family) [61l,74].…”

Section: Reduction Of C C Double Bondsmentioning

confidence: 99%

“…Ligand 33b induced the best enantioselectivity for some enol carbamates and caused in most cases a switch of configuration compared to the parent ligand [37].…”

Section: Reduction Of C C Double Bondsmentioning

confidence: 99%

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Synthesis and application of chiral monodentate phosphines in asymmetric hydrogenation

Erre

Enthaler

Junge

et al. 2008

Coordination Chemistry Reviews

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112

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Section: Design and Synthesis Of Chiral Monophosphinessupporting

confidence: 62%

Section: Reduction Of C C Double Bondsmentioning

confidence: 99%

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Synthesis and application of chiral monodentate phosphines in asymmetric hydrogenation

Erre

Enthaler

Junge

et al. 2008

Coordination Chemistry Reviews

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112

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“…Chiral phosphines 8 are still of great significance, and we chose to explore binaphthyl systems as the CPSs of P-chirogenic phosphines are known to racemize. 85 The oxides of chiral phosphepines permit structure elaboration, 86 and our new method rapidly afforded ( S )-Ph-BINEPINE ( 12 ) 87 (96% yield). ( R )-MeO-MOP ( 13 ) 88 was also readily synthesized (99%).…”

Section: Resultsmentioning

confidence: 99%

A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts

et al. 2021

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The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.

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“…At present the library of binepine ligands includes structurally diverse derivatives featuring different substituents at the P‐donor1c, 3b or at the benzylic carbons 1c. 3a No example has yet been reported where the phosphepine ring has been fused with a diaryl template other than binaphthalene.…”

Section: Methodsmentioning

confidence: 99%

Dimethoxydibenzophosphepine: An Axially Chiral Monophosphane for Efficient Asymmetric Catalysis

2010

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Binepines are monodentate phosphanes characterized by a seven-membered phosphepine ring in a C 2 -symmetrical environment created by the atropisomeric binaphthalene template. They incorporate an endocyclic P-donor atom and feature a stereogenic axis as unique chiral element (Figure 1).The first representative of this class, P-phenyl binaphthophosphepine (Ph-binepine 1, Figure 1) was synthesized in 1994. [1] Binepines facilitate very high stereoselectivities in a variety of asymmetric processes, both as organocatalysts [2] and as ligands in metal catalysts. The range of transition metal binepine catalysts screened with remarkable success is quite wide and, to date, comprises Rh, [3] Ru, [4] Pd, [5] Pt, [6] Cu, [7] and Ni [8] complexes.At present the library of binepine ligands includes structurally diverse derivatives featuring different substituents at the Pdonor [1c, 3b] or at the benzylic carbons. [1c, 3a] No example has yet been reported where the phosphepine ring has been fused with a diaryl template other than binaphthalene.Herein we report the synthesis of (R)-7 (Scheme 1), the first member of a new class of diphenyl-templated phosphepines, and its performances in some basic asymmetric catalysis.In the binepine synthesis, the phosphepine ring is created by reacting the dilithium-N,N,N',N'-tetramethylethylenediamine (TMEDA) adduct obtained from enantiopure 2,2'-dimethyl-1,1'binaphthalene with a suitable phosphorus bis-electrophile. To exploit the same strategy in the preparation of (R)-7, a straight-

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Enantioselective rhodium-catalyzed hydrogenation of enol carbamates in the presence of monodentate phosphines

Cited by 37 publications

References 65 publications

Synthesis and application of chiral monodentate phosphines in asymmetric hydrogenation

Synthesis and application of chiral monodentate phosphines in asymmetric hydrogenation

A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts

Dimethoxydibenzophosphepine: An Axially Chiral Monophosphane for Efficient Asymmetric Catalysis

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