Cyclocondensation of alpha-aminonitriles and enones: a short access to 3,4-dihydro-2H-pyrrole 2-carbonitriles and 2,3,5-trisubstituted pyrroles.

The reaction of alpha,beta-unsaturated carbonyl compounds with aminoacetonitrile hydrochloride furnishes 3,5-disubstituted 3,4-dihydro-2H-pyrrole-2-carbonitriles in a one-pot reaction sequence. While these products can serve as starting materials for the preparation of polysubstituted pyrrolizidines, they are kinetically stable against the base-induced elimination of HCN. In contrast, their 2-substituted analogues obtained from alpha-substituted alpha-aminonitriles can be readily converted to the corresponding 2,3,5-trisubstituted pyrroles under microwave irradiation. The key step presumably involves the thermal electrocyclization of a stabilized 2-azapentadienyl anion formed by condensatio…

One-Pot Synthesis of (.+-.)-Crispine A and Its C-Ring-Substituted Analogues.

An Aldimine Cross-Coupling for the Diastereoselective Synthesis of Unsymmetrical 1,2-Diamines

Addition of α-Aminonitriles to α,β-Unsaturated Carbonyl Compounds: A One-Pot Synthesis of Polysubstituted Pyrrolidines.

The vinylogous addition of deprotonated N-alkyl-α-aminonitriles to α,β-unsaturated carbonyl compounds yields cyclic intermediates which can be reduced to form polysubstituted pyrrolidines in a one-pot reaction sequence. Since the cyano substituent is lost in the reduction step, the aminonitriles serve as easily accessible (N-alkylamino)-substituted carbanion equivalents.

ChemInform Abstract: Cyclocondensation of α-Aminonitriles and Enones: A Short Access to 3,4-Dihydro-2H-pyrrole 2-Carbonitriles and 2,3,5-Trisubstituted Pyrroles.

The reaction of α,β-unsaturated carbonyl compounds with aminoacetonitrile hydrochloride furnishes 3,5-disubstituted 3,4-dihydro-2H-pyrrole-2-carbonitriles in a one-pot reaction sequence. While these products can serve as starting materials for the preparation of polysubstituted pyrrolizidines, they are kinetically stable against the base-induced elimination of HCN. In contrast, their 2-substituted analogues obtained from α-substituted α-aminonitriles can be readily converted to the corresponding 2,3,5-trisubstituted pyrroles under microwave irradiation. The key step presumably involves the thermal electrocyclization of a stabilized 2-azapentadienyl anion formed by condensation of the reacta…

A Short Synthesis of Polysubstituted Pyrrolidines via α-(Alkylidene­amino)nitriles

α-(Alkylideneamino)nitriles can be deprotonated under mild conditions. Their conjugated anions react with enones in a 1,4-addition to yield δ-keto-α-(alkylideneamino)nitriles which in turn can be reduced to form pyrrolidines in a one-pot reaction sequence.

One-Pot Synthesis of Polysubstituted Pyrrolidines from Aminonitriles

α-Aminonitriles with a mono- or unsubstituted amino group as well as a-(alkylideneamino)nitriles can be employed as easily accessible α-aminocarbanion equivalents. Their α-deprotonation yields stabilized carbanions, whichundergo smooth 1,4-addition to α,β-unsaturated carbonyl compounds. The resulting δ-ketoα-aminonitriles can be reductively cyclized to form polysubstituted pyrrolidines.

Eine gekreuzte Aldiminkupplung zur diastereoselektiven Synthese von unsymmetrischen 1,2-Diaminen

One-Pot Synthesis of (±)-Crispine A and Its C-Ring-Substituted Analogs

A straightforward access to crispine A and C-ring-substituted analogs by 1,4-addition of a deprotonated α-amino nitrile to α,β-unsaturated carbonyl compounds is described. If the reduction step is omitted, substituted 5,6-dihydropyrrolo[2,1-a]isoquinolines can be obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)