Grignard reagents aziridine synthesis

The Hoch-Campbell aziridine synthesis entails treatment of ketoximes with excess Grignard reagents and subsequent hydrolysis of the organometallic complex. ... 

Aziridines are obtained in a novel one-pot synthesis (Scheme 37) by reacting l-(triphenylphosphoranylidenamine)benzotriazole (BETMIP) 68 with Grignard reagents. The resulting aliphatic iV-substituted iminophos-phoranes (69) are converted in situ with oxiranes to give aziridines (70) (90S565). 

Aryl alkyl ketoximes also react with aryl or alkyl Grignard reagents to give substituted ethylenimines [44, 45]. Additional methods for the synthesis of ethylenimines (aziridines) is found in Dermer and Ham [lb]. 

Azirines have also been shown to be likely intermediates in the Campbell aziridine synthesis.62 This reaction is analogous to the Neber reaction in which the intermediate azirine is hydrolyzed to the aminoketone. Here the proposed azirine intermediate prepared from oxime (144) reacts with a Grignard reagent to give the aziridine (145). 

Synthesis of aziridines from ketoximes and Grignard reagents... 

A simple and efficient stereoselective synthesis of aziridine-2-phosphonate 781 and phosphine oxide 782 was achieved by diastereoselective addition of Grignard reagents to 277-azirine phosphonate 779 and phosphine oxide 780. Addition of benzenethiol and heterocyclic amines proceeded in an analogous manner to yield functionalized aziridines 783 and 784 (Scheme 188). 

Additions of nucleophiles to vinyl aziridines provide the issue of selectivity of 1,2 (Sn2) or 1,4 (Sn2 ) additions. During a very short efficient synthesis of pancratistatin, Hudlicky et al. chose to open a vinylaziridine 156 with an aromatic cuprate 157 <1996JA10752>. Formation of the trans-, Z adduct 158 was accomplished in 75% chemical yield (Equation 42). They found that the addition of simple lower order cuprates or Grignard reagents (aliphatic or aromatic) reacted to give the syn-, A addition, whereas higher-order cuprates gave the trans-, Z product. 

Nitrosolysis of camphor ethyl acetal with ethanolic ethyl nitrite in sulphur dioxide yields the orthoester oxime (205) which is rapidly dehydrated by excess acetal to the orthoester nitrile which then reacts with sulphur dioxide to form the ester nitrile and diethyl sulphite.Further papers in this section include the full paper on ozonolysis of silyl ethers (Vol. 5, p. 33), another synthesis of camphor-enol trimethylsilyl ether (cf. Vol. 6, p. 41)/°° the conversion of camphor oxime with Grignard reagents into the corresponding imine with no aziridine formation/° the preparation of (206) by treating bornylene with trichloroacetyl isocyanate/ the oxidation of thiocam-phor to the 5-oxide and alkylation in the presence of thallium(i) ethoxide to a/S-unsaturated sulphoxides/ and the free-radical C-3 alkylation of camphor with alkenes. " ... 

Palacios et al. described the stereoselective synthesis of fluoroalkyl-substituted aziridine-phosphine oxides by the diastereoselective addition of Grignard reagents to functionalized ketoxime-phosphine oxides. Aziridines were used as intermediates for the regioselective S5mthesis of fluorine containing P-aminophosphine oxides. Products of the latter type could also be obtained by reduction of the ketoxime-phosphine oxides with sodium borohydride (Scheme 39). ... 

---