Mechanistic approaches to asymmetric synthesis of aziridines from guanidinium ylides and aryl aldehydes

Haga, Toyokazu; Ishikawa, Tsutomu

doi:10.1016/j.tet.2005.01.088

Cited by 42 publications

(31 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…21) A mixture of (S,S)-40 and a benzaldehyde was stirred in THF in the presence of TMG at 25°C for 5 h (step 1) and then treated with acetic anhydride (Ac 2 O) in place of SiO 2 at room temperature until disappearance of the polar intermediate on thin-layer chromatography (step 2). The aziridination reactions could be classified into four groups based on the nature of benzaldehydes used: 1) group A, which includes benzaldehydes with strong electron-donating group (EDG) (XϭO n Bu and OMe), is characterized by a very slow step 1 and a very rapid step 2, showing excellent diastereoselectivity and enantioselectivity a) The reaction was carried out using the same ArCHO under the conditions shown in Table 2.…”

Section: Guanidinium Ylides For Aziridine Formation (Role As Nitrogenmentioning

confidence: 99%

Guanidine Chemistry

Ishikawa

2010

Chem. Pharm. Bull.

Self Cite

View full text Add to dashboard Cite

Guanidines are categorized as strong organobases; however, their catalytic utility in organic synthesis has not been discussed thoroughly. The author's group has extensively and systematically studied their potential ability focusing on: 1) modified guanidines as chiral auxiliaries; 2) guanidinium ylides for aziridine formation; 3) the affinity of bisguanidine for proton and metal salts; and 4) the potential chirality of bisguanidine. Under the first topic, a variety of chiral guanidines was designed by the introduction of chirality on the three guanidinyl nitrogens, and the modified guanidines prepared using our original methods were found to be effective not only in catalytic but also in stoichiometric asymmetric syntheses. Under the second topic, the reaction of guanidinium salts carrying a glycinate function with aromatic or unsaturated aldehydes under basic conditions unexpectedly afforded aziridine-2-carboxylates, which were available as useful building blocks in organic synthesis due to their convertibility to functionalized amino acid derivatives in the ring-opening reaction, together with urea compounds recyclable to the starting guanidinium salts. The introduction of a chiral template to the guanidinium salt allowed us to expand the cyclic aziridination reaction to an asymmetric version. Under the third topic, effective complexabilty of bisguanidines with either proton or metal ions in water was observed, suggesting their possible application to the removal of toxic substances from polluted water and recovery of rare elements as material sources. Under the final topic, monomethylation or monoethylation of bisguanidine afforded a chiral product via asymmetric crystallization, indicating that bisguanidines have a potential chiral character due to the plane asymmetry.

show abstract

Section: Guanidinium Ylides For Aziridine Formation (Role As Nitrogenmentioning

confidence: 99%

Guanidine Chemistry

Ishikawa

2010

Chem. Pharm. Bull.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Quagliato et al [17] had reported the chemical conversion of the a-amino acid function to a a-methylamine system. To show the utility of the 3-aryl-1-benzylaziridine-2-carboxylates as chiral tools for synthetic purposes, we independently carried out the asymmetric synthesis of an amphetamine-type compound (i.e., 1-arylpropan-2-amines) from tert-butyl (+)-trans-3-(1,3-benzodioxol-5-yl)-1-benzylaziridine-2-carboxylate ((+)-trans-3c), obtained by the aziridination reaction [12] with (R,R)-guanidinium salt (R,R)-1 (X = Ph, R 1 = Bn, R 2 = t Bu; see Scheme 2), after a slight modification of the reported method [17] (Scheme 6). Thus, a solution of (+)-trans-3c (87% ee) in MeOH was hydrogenated over Pd(OH) 2 /C in the presence of di(tert-butyl) dicarbonate ((Boc) 2 O) to give the expected N-Boc-protected amino ester (+)-11 in high yield, as reported earlier [10].…”

mentioning

confidence: 99%

“…DMF, Et 3 N, MeCN, and EtOH were distilled from calcium hydride (CaH 2 ). Starting aziridines were prepared according to the reported procedure [12]. Column chromatography (CC): silica gel 60 (spherical, 70 -230 mesh; Fuji Silysia FL100D or Kanto Chemicals).…”

mentioning

confidence: 99%

Ring‐Opening Reactions of 3‐Aryl‐1‐benzylaziridine‐2‐carboxylates and Application to the Asymmetric Synthesis of an Amphetamine‐Type Compound

Manaka

Nagayama

Desadee

et al. 2007

Helvetica Chimica Acta

Self Cite

View full text Add to dashboard Cite

Nucleophilic ring-opening reactions of 3-aryl-1-benzylaziridine-2-carboxylates were examined by using O-nucleophiles and aromatic C-nucleophiles. The stereospecificity was found to depend on substrates and conditions used. Configuration inversion at C(3) was observed with O-nucleophiles as a major reaction path in the ring-opening reactions of aziridines carrying an electron-poor aromatic moiety, whereas mixtures containing preferentially the syn-diastereoisomer were generally obtained when electron-rich aziridines were used (Tables 1 -3). In the reactions of electron-rich aziridines with C-nucleophiles, S N 2 reactions yielding anti-type products were observed ( Table 4). Reductive ring-opening reaction by catalytic hydrogenation of (+)-trans-(2S,3R)-3-(1,3-benzodioxol-5-yl)aziridine-2-carboxylate (+)-trans-3c afforded the corresponding a-amino acid derivative, which was smoothly transformed into (+)-tert-butyl [(1R)-2-(1,3-benzodioxol-5-yl)-1-methylethyl]carbamate((+)-14) with high retention of optical purity (Scheme 6). ; the former category includes electron-withdrawing substituents such as tosyl or acyl functions, whereas a H-atom and alkyl substituents are typical for the latter one. Although the reactivity of activated aziridines has been well investigated, there are only limited reports [6 -9] on unactivated aziridines.Recently, we have reported an atom-economical aziridine synthesis from guanidinium salts 1 (obtained from the ureas 4) and arenecarboxaldehydes 2 [10] (or unsaturated aldehydes [11]) applicable to asymmetric synthesis, in which 1-alkyl-3-arylaziridine-2-carboxylates 3 (or the corresponding unsaturated derivatives) are produced, as shown in Scheme 2. In this paper, we present the ring-opening reactions of N-benzylaziridine-2-carboxylates, prepared by the above reaction, with O-nucleophiles and aromatic C-nucleophiles and application to the asymmetric synthesis of an amphetaminetype compound from the reductively ring-opened product.

show abstract

“…As metodologias mais recentes [121][122][123][124][125][126][127][128][129][130][131] de preparação de aziridinas não levam em conta apenas a sua obtenção em altos rendimentos e seletividade, mas também a necessidade de se empregar reagentes mais acessíveis e gerar quantidades reduzidas de sub-produtos tó-xicos. Avanços na síntese assimétrica de aziridinas vêm permitindo um maior entendimento dos parâmetros necessários para a obtenção destes blocos de construção quirais com alta pureza óptica e economia atômica.…”

Section: Conclusãounclassified

Recentes avanços na preparação de aziridinas. Aplicações sintéticas e implicações mecanísticas

Bisol¹,

Sá²

2007

Quím. Nova

View full text Add to dashboard Cite

Recebido em 22/8/05; aceito em 3/2/06; publicado na web em 30/8/06RECENT ADVANCES IN THE PREPARATION OF AZIRIDINES AND THEIR APPLICATION IN ORGANIC SYNTHESIS. This article surveys a selection of the most recent advances in aziridine synthesis. Novel synthetic methods and new insights into existing methodologies for the selective construction of the title compounds reported in the past decade are discussed in terms of synthetic applicability and environmentally benign conditions. Mechanisms involving stereoselective preparation of structurally diverse aziridines are also presented in order to highlight the most important issues associated with the synthesis of these versatile building blocks.

show abstract

Mechanistic approaches to asymmetric synthesis of aziridines from guanidinium ylides and aryl aldehydes

Cited by 42 publications

References 8 publications

Guanidine Chemistry

Guanidine Chemistry

Ring‐Opening Reactions of 3‐Aryl‐1‐benzylaziridine‐2‐carboxylates and Application to the Asymmetric Synthesis of an Amphetamine‐Type Compound

Recentes avanços na preparação de aziridinas. Aplicações sintéticas e implicações mecanísticas

Contact Info

Product

Resources

About