β-Lactam formation via rhodium(II) catalyzed carbon-hydrogen insertion reactions of α-diazo amides

Doyle, Michael P.; Oon, Su Min; Heide, F. R. Van Der; Brown, Carol B.

doi:10.1016/s0960-894x(01)80966-5

Cited by 24 publications

(8 citation statements)

References 33 publications

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“…The novelty of this β-lactam synthesis consists of (1) the use of 1-alkoxycyclopropylamines 5 for the first time, (2) the use of geminally dialkylated cyclopropanone adducts for the first time, (3) the synthesis of previously almost inaccessible (cfr. only one recent report ) 1,4,4-trialkyl- 2-azetidinones, (4) the regiospecific nature of this transformation, and (5) the use of α-chloro ketones as a new source of β-lactams.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of 4,4-Disubstituted β-Lactams by Regiospecific Electrophile- and Silver-Induced Ring Expansion of 2,2-Disubstituted 1-Methoxycyclopropylamines

1996

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2,2-Disubstituted 1-methoxycyclopropylamines underwent regiospecific ring expansion to 1,4,4-trisubstituted 2-azetidinones by N-chlorination with tert-butyl hypochlorite and subsequent rearrangement with silver tetrafluoroborate. Upon thermolysis, 4,4-disubstituted beta-lactams suffer a characteristic ring opening to afford beta,gamma-unsaturated carboxylic amides. The reduction of 1,4,4-trisubstituted 2-azetidinones with lithium aluminum hydride afforded 1,2,2-trisubstituted azetidines.

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Section: Resultsmentioning

confidence: 99%

“…Calcd (Found) for 9a , C 8 H 15 NO: C, 68.04; H, 10.71; N, 9.92 (C, 68.12; H, 10.79; N, 9.79). This compound was recently prepared for the first time by intramolecular rhodium(II)-catalyzed insertion of α-diazo carboxylic amides …”

Section: Methodsmentioning

confidence: 99%

Synthesis of 4,4-Disubstituted β-Lactams by Regiospecific Electrophile- and Silver-Induced Ring Expansion of 2,2-Disubstituted 1-Methoxycyclopropylamines

1996

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“…The dirhodium(II)-catalyzed intramolecular metal carbene C−H insertion transformation holds considerable promise as a useful methodology for organic synthesis. − However, with multiple sites for insertion, effective control of regioselectivity and stereoselectivity can be a challenge of unmistakable complexity. Preference exists for the formation of five-membered rings, and reactivity for insertion into C−H bonds follows the order tertiary > secondary ≫ primary. , Heteroatoms that include oxygen and nitrogen activate adjacent C−H bonds for insertion, − but conformational effects can and do override electronic preferences − and enantiocontrol − set further restrictions for this methodology.…”

Section: Introductionmentioning

confidence: 99%

“…Preference exists for the formation of five-membered rings, and reactivity for insertion into C−H bonds follows the order tertiary > secondary ≫ primary. , Heteroatoms that include oxygen and nitrogen activate adjacent C−H bonds for insertion, − but conformational effects can and do override electronic preferences − and enantiocontrol − set further restrictions for this methodology. …”

Section: Introductionmentioning

confidence: 99%

Chiral Catalyst Controlled Diastereoselection and Regioselection in Intramolecular Carbon−Hydrogen Insertion Reactions of Diazoacetates

1996

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Individual enantiomers of substituted cyclohexyl diazoacetates or 2-octyl diazoacetates matched with a configurationally suitable chiral dirhodium(II) carboxamidate catalyst provide an effective methodology for the synthesis of lactones with exceptional diastereo- and regiocontrol. Enantiomerically pure (1S,2R)-cis-2-methylcyclohexyl diazoacetate forms the all-cis-(1R,5R,9R)-9-methyl-2-oxabicyclo[4.3.0]nonan-3-one with complete diastereocontrol in reactions catalyzed by dirhodium(II) tetrakis[methyl 1-(3-phenylpropanoyl)-2-oxoimidazolidine-4(R)-carboxylate], Rh2(4(S)-MPPIM)4, but the configurational mismatch results in a mixture of products. The same diazoacetate produces (1S,5R)-5-methyl-2-oxabicyclo[4.3.0]nonan-3-one with virtually complete selectivity by catalysis with dirhodium(II) tetrakis[methyl 2-oxopyrrolidine-5(S)-carboxylate], Rh2(5(S)-MEPY)4. Similarly high stereo- and regiocontrol is also achieved with enantiomerically pure trans-2-methylcyclohexyl diazoacetates. Product control from insertion reactions of d- or l-menthyl diazoacetate and (+)-neomenthyl diazoacetate from the configurational match with dirhodium(II) catalyst results in the formation of one C−H insertion product in high yield. The exceedingly high product diastereoselection observed in these reactions is consistent with virtually exclusive insertion into equatorial C−H bonds. The catalyst-dependent selective formation of a cis-disubstituted γ-butyrolactone or a β-lactone from 2-octyl diazoacetate has been achieved. Control of product diastereoselectivity and regioselectivity in C−H insertion reactions is explained by conformational suitability in configurational match/mismatch of catalyst and carbene.

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“…For example, the reaction of N - t -butyl- N -arylmethyl-α-diazoacetamides 60 catalyzed by Rh 2 (OAc) 4 gave the trans -β-lactams 62 exclusively via a Rh-carbenoid species 61 in 90–98% yield (Scheme 15). 67,68 …”

Section: Asymmetric Synthesis Of β-Lactamsmentioning

confidence: 99%

Advances in the chemistry of ?-lactam and its medicinal applications

2012

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β-Lactam formation via rhodium(II) catalyzed carbon-hydrogen insertion reactions of α-diazo amides

Cited by 24 publications

References 33 publications

Synthesis of 4,4-Disubstituted β-Lactams by Regiospecific Electrophile- and Silver-Induced Ring Expansion of 2,2-Disubstituted 1-Methoxycyclopropylamines

Synthesis of 4,4-Disubstituted β-Lactams by Regiospecific Electrophile- and Silver-Induced Ring Expansion of 2,2-Disubstituted 1-Methoxycyclopropylamines

Chiral Catalyst Controlled Diastereoselection and Regioselection in Intramolecular Carbon−Hydrogen Insertion Reactions of Diazoacetates

Advances in the chemistry of ?-lactam and its medicinal applications

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