Observations on the direct amidocyclopropanation of alkenes using organozinc carbenoids

Motherwell, William B.; Bégis, Guillaume; Cladingboel, David E.; Jerome, Laure; Sheppard, Tom D.

doi:10.1016/j.tet.2007.03.027

Cited by 23 publications

(6 citation statements)

References 33 publications

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“…[25,26] The Lewis acidic salt can then assist the departure of the cyano group to lead to the metalated iminium salt 29, which is a species that has precedents in literature. [27][28][29] From this point, several possibilities can be considered. First, the postulated zincioiminium ion 29 (or the parent zincated a-amino nitrile) is a carbenoid species.…”

Section: Mechanistic Considerationsmentioning

confidence: 99%

Cyclization of Zincated α‐N‐Homoallylamino Nitriles: A New Entry to Enantiopure 2,3‐Methanopyrrolidines

Ouizem

Cheramy

Botuha

et al. 2010

Chemistry A European J

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Stereoselective cyclization of zincated α-N-homoallylamino nitriles has been developed. Following treatment with lithium diisopropylamide (LDA) and transmetalation with zinc bromide, α-N-(1-phenylethyl)-N-homoallylamino nitriles lead to 2,3-methanopyrrolidines in moderate to good yields (up to 66 %) and excellent selectivities (up to >98:2). With substrates derived from α-branched homoallylic amines, a stereospecific inversion of the homoallylic stereogenic center was observed. To account for this, a mechanistic rationale involving the formation of zincioiminium ions from zincated α-amino nitriles is put forward. 2,3-Methanopyrrolidines should then arise from a sequence involving an aza-Cope rearrangement providing a configurationally stable (2-azoniaallyl)zinc species that then undergoes a [3+2] cycloaddition reaction.

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Section: Mechanistic Considerationsmentioning

confidence: 99%

Cyclization of Zincated α‐N‐Homoallylamino Nitriles: A New Entry to Enantiopure 2,3‐Methanopyrrolidines

Ouizem

Cheramy

Botuha

et al. 2010

Chemistry A European J

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“…[2] Furthermore, aminocyclopropanes in particular are incorporated in a number of drugs such as tranylcypromine [3] and trovafloxacin [4] or in aminocyclopropanecarboxylic acids, [5] but also as key elements in natural products such as coronatine [6] or belactosin A ( Figure 1). [7] A number of syntheses have been disclosed, including the cyclopropanation of enamines and aminonitriles, [8] the amidocyclopropanation of alkenes, [9] the Curtius rearrangement, [10] the reductive amination of cyclopropanone acetals [11] or the reduction of nitrocyclopropanes, [12] although not every method has been widely applied. For enantiomerically pure products -essential for drug synthesis -a number of approaches have been successfully applied, [13] one of the most prominent recent examples being the de Meijere [14] variation of the Kulinkovich [15] hydroxycyclopropanation.…”

Section: Introductionmentioning

confidence: 99%

Enantiomerically Pure Cyclopropylamines from Cyclopropylboronic Esters

Pietruszka

Solduga

2009

Eur J Org Chem

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Cyclopropylamines are versatile intermediates and products both in organic synthesis in general and for active substances in particular. Although the synthesis of the corresponding enantiomerically pure cyclopropylboronic esters had been established previously, the C–B to C–N transformation was elusive. A detailed study directed towards the synthesis of several enantiomerically pure cyclopropylamines is disclosed; tranylcypromine [(1S,2R)‐36] and the known belactosin A intermediate 43 were both obtained by use of trifluoroborates as key intermediates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…The relatively simple access to both classes of N -dimethoxymethyl derivatives, 8 and 12, enables their further exploration in organic synthesis. In the case of products of type 12, some analogous N -diethoxymethyl derivatives have already been synthesized, however, by a completely different reaction, and utilized for the generation of a new type of carbenoids (19). Our approach offers an alternative, efficient method for the preparation of this type of synthetically useful compounds.…”

Section: Resultsmentioning

confidence: 99%

Chemoselective insertion of dimethoxycarbene into the N – H bond of thiolactams with diverse ring size

Mlostoń

Heimgartner

2009

Journal of Sulfur Chemistry

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This paper is dedicated to Professor Juzo Nakayama on the occasion of his 65th birthday and retirement, and for his outstanding contributions to the organic chemistry of sulfur.Thermal decomposition of 2,5-dihydro-1,3,4-oxadiazole 4 in toluene solution in the presence of thiolactams 7 or corresponding lactams 11 result in the chemoselective formation of the N -(dimethoxy)methyl derivatives 8 and 12, respectively. The products of both types are formed via insertion of dimethoxycarbene 2a into the N−H bonds. A reaction mechanism via the intermediate ion pair 14/15 or a complex of type 13 is postulated to explain the formation of the products.

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Observations on the direct amidocyclopropanation of alkenes using organozinc carbenoids

Cited by 23 publications

References 33 publications

Cyclization of Zincated α‐N‐Homoallylamino Nitriles: A New Entry to Enantiopure 2,3‐Methanopyrrolidines

Cyclization of Zincated α‐N‐Homoallylamino Nitriles: A New Entry to Enantiopure 2,3‐Methanopyrrolidines

Enantiomerically Pure Cyclopropylamines from Cyclopropylboronic Esters

Chemoselective insertion of dimethoxycarbene into the N – H bond of thiolactams with diverse ring size

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