Generation and electrophilic substitution reactions of 3-lithio-2-methyleneaziridines

Methyleneaziridines: Unusual Vehicles for Organic Synthesis

“…Many common electrophilic quenches for carbanions such as MeOD, MeI, PhCH 2 Br, CH 2 =CHCH 2 Br, PhCHO, Ph 2 CO, Me 3 SiCl and Bu 3 SnCl can be used successfully. 37 However, the reaction is limited to the formation of monosubstituted products at C-3, as we have been unable to identify conditions to repeat the deprotonation-alkylation sequence.…”

Synthesis and applications of methyleneaziridines

“…19 This organolithium species successfully (Scheme 8). 20 However, the reaction was limited to the formation of monosubstituted products at C-3.…”

“…In the presence of an organometallic promoter, the ringopening of MAs 86 with carbon-based nucleophile would produce a metalloenamine 87, which might further undergo C- 20 A solution of 2-lithiated MA 90, prepared by the treatment of 25 with butyllithium/TMEDA in ether, was quenched by H 2 O to give a pale-yellow crystal, which was sensitive to air and moisture. Elemental analysis and mass spectrum conrmed the product structure as a dimer 89.…”

Metalated heterocycles in organic synthesis: Recent applications

“…134 The process can be performed diastereoselectively when the starting aziridine bears a (S)-α-methylbenzyl group on the nitrogen atom, 135 as in the case of aziridinyllithium species 57, generated by deprotonation of the aziridine 56, which reacted with an electrophile such as allyl bromide affording the diastereoselectively enriched compound 58 (Scheme 18). 134 The direct lithiation of aziridines using secbutyllithium/TMEDA has been facilitated when the next carbon atom is occupied by an oxazolinyl group, which can also affect the stereoselectivity of the further reaction with electrophiles due to their complexating properties. 136 In addition, the formation of an aziridineborane complex facilitates the α-metalation and the control of the stereochemistry, 137 the process being also performed with enantiopure complexes.…”