77414-34-7

Upstream product

• 92-83-1 xanthene 
• 98943-70-5 cis-1-benzoyl-2-benzyl-2-phenylaziridine 
• 613-31-0 9,10-dihydroanthracene 
• 98-88-4 benzoyl chloride 
• 1605-08-9 cis-2-benzyl-3-phenylaziridine 
• 4275-43-8 1-benzyl-2-phenylethylamine 

Downstream Products

• 77988-88-6 3-benzyl-1-phenyl-3,4-dihydro-isoquinoline 

Relevant academic research and scientific papers

Reactions of N-acylaziridines with sodium metal and sodium naphthalenide. Elimination of olefines

Reactions of N-acylaziridines 1a-g (N-benzoyl except 1d) with sodium or naphthalenide N.- in THF provide a variety of products that usually arise via the aziridino ketyls 2. Homolytic ring opening of 2 generates the amidatoalkyl radicals 3. Only with a very short reaction time were small amounts of benzil or benzoylnaphthalenes obtained indicating a reversible trapping of 2 by dimerization or coupling with N.-. Homolysis of 2 produced always the more stable 3 apart from reactions of monomethylaziridines 1c,d where the primary radical i-3c,d is kinetically favoured. The amides R1CONHCHR4CHR2R3 (9, isopropylamides i-9c,d from 1c,d) were usually the main products. 9 arise from 3 either by H atom abstraction from THF (probably in sodium metal runs) or by reduction of 3 to carbanions 5 that abstract a proton from THF (N.- runs). Addition of 5a (R2-4 = H) to 1a gives finally the ketone 8a. Self reaction of primary radical 3a is dimerization. Self reaction of tertiary or secondary radicals is disproportionation when an allylamide arises. This isomerizes to an enamide unless it is conjugated. R2R3C=CHR4 and R1CONH2 arise (probably) always. The mechanism, possibly a cyclic process of anion 6, is not clear. Johann Ambrosius Barth 1996.

Single Electron Transfer versus Nucleophilic Ring Opening in Reactions of Cis-Trans Pairs of Activated 2-Phenylaziridines. Strong Influence of Nitrogen Pyramid for N-Benzoylaziridines

Activated 2-phenylaziridines with a second substituent R in position 3 were made to react with xanthyl anion X(1-).Nucleophilic ring opening is the only reaction that occurs with sulfonyl activation.The analogous N-benzoylaziridines 1 undergo this type of ring opening when the two substituents Ph and R are trans.The cis isomers (cis-1, Ph and R cis) react in this manner to a negligible extent if any.The (nearly) exclusive ring cleavage reaction of cis-1 is C-N homolysis of an intermediate ketyl formed by single electron transfer (SET) from X(1-).This cis-trans phenomenon is in accordance with the hypothesis that the two competing reactions depend in an opposite manner on the steepness of the nitrogen pyramid.A predominant or exclusive final result of SET is reductive aziridine opening and dimerization of the xanthyl radical X(.).Formation of both diastereomers of the amidoethylated xanthene in one case (R = Me) is evidence for a cross combination of X(.) with the radical formed by homolytic ring opening.Cross combination is also a likely path for R = H (no cis-trans isomerism), in addition to reductive ring opening. cis-Aziridines with dimethylcarbamoyl on nitrogen do not react via SET since the ketyl is not stabilized and therefore difficult to generate.Carbonyl attack on both types of acylaziridines competes more or less successfully with the two ring cleavage reactions.

HOMOLYTIC AZIRIDINE OPENING (AZA VARIANT OF CYCLOPROPYLCARBINYL-HOMOALLYL REARRANGEMENT) BY ADDITION OF TRIBUTYLTIN RADICAL TO N-ACYLAZIRIDINES. FACTORS CONTRIBUTING TO THE REGIOSELECTIVITY

AIBN initiated reaction of N-acylaziridines 1 with Bu3SnH in refluxing benzene provided products 5 and 8 of reductive ring opening.Yields (practically quantitative in most cases) fell drastically with steric hindrance of the addition of Bu3Sn to the acyl oxygen of 1.They depended to some extent on the experimental conditions for hydrogen capturing when aziridine homolysis provided a primary radical 3 or 6.The regioselectivity of (probably reversible) ring homolysis can be understood in terms of the stability of the arising radical (3, 6), of stereoelectronic control (e.g. 1i as compared to 1h) and of frontier orbital interactions (1j).A possible difference in bond lengths as explanation for the formation of the primary radical from 1j did not find support from an X-ray structure analysis of N-tosyl-2-methyl-aziridine 11.Isomeric products were obtained only twice (1i, 1j) with a dependence of the ratio 5j:8j on concentration and hydrogen isotope of Bu3SnH.No such dependence was found for the ratio 5:14 (reduction without and with an intervening cyclization of 3 leading to a pyrrolidone) obtained from the N-cinnamoylaziridine 1l.This ratio (1:9 for 1l and 1:3 for 1n) must reflect the E-Z isomers in 3.The observed preference for the formation of E-3 from 2 can be explained by stereoelectronic and steric effects.A cinnamoyl double bond in 5 was saturated depending on experimental conditions.

Highly Regioselective Ring Cleavage of N-Acylaziridines by "Anthracene Hydride" (Anion of 9,10-Dihydroanthracene). Intermediacy of a Carbonyl Adduct. Influence of Nitrogen Inversion on the Ring Opening?

Anthracene hydride AH- reacts with N-acylaziridines by reductive opening of the aziridine ring and/or amidoethylation of AH-.When the two aziridine carbons are differently substituted, in both reactions only that bond is broken which can form the more stable carbon radical quite in accord with the intermediacy of a radical anion (ketyl) 14 and with the known homolytic cleavage of 14 forming the radical 15.The extra electron in 14 is provided by AH- being oxidized to the radical AH., which can react with 15 either by radical combination or by hydrogen transfer.The reaction of AH- with N-aroylaziridines can be interrupted at the stage of the carbonyl adduct 5 as is shown by the isolation of the ketones 7a,b.So, 5 (R4 = aryl) is considered to be in equilibrium with the radical pair AH./14.The conversion of 5 into the final products progresses as expected from its structure apart from the observed retardation by a phenyl substituent in the aziridine ring (3a, 4a).This retardation is tentatively explained by a hypothesis assuming ring opening of 14 to occur in the transition state of nitrogen inversion.The anion X- of xanthene resembles AH- in its reactivity.Both carbanions react with N-sulfonylaziridines as expected from an SN2 mechanism.

The mechanism of the Bischler-Napieralski Reaction

The Bischler-Napieralski dihydroisoquinoline synthesis was proven to occur via imidoyl chlorides and the corresponding nitrilium salt.Two-step process required much milder conditions (20 degC - 50 degC) compared to drastic classical conditions of refluxing at 100 degC - 200 degC.The Bischler-Napieralski reaction is shown to share a common intermediate with two other well-known reactions: the von Braun and the Ritter reactions

Reversal of the Ritter Reaction as Observed Under Electron Impact Conditions

Fragmentations of various 2-phenethylamides, trifluoroacylimidates and imidoyl triflouromethyl sulfonates have been studied and a pathway for the formation of retro-Ritter reaction products is proposed.