Nitrocyclopropanes from nitrodiazomethanes. Preparation and reactivity

Acceptor/Acceptor‐Substituted Diazo Reagents for Carbene Transfers: Cobalt‐Catalyzed Asymmetric Z‐Cyclopropanation of Alkenes with α‐Nitrodiazoacetates

“…While the ineffectiveness of [Co(tpp)] (tpp = tetraphenylporphyrin) for the reaction might be expected (Table 1, entry 1), it was a disappointing revelation that [Co(P6)], which was previously shown to be the best catalyst for asymmetric cyclopropanation with diazosulfones, [6e] gave an even poorer result (Table 1, entry 7). However, in contrast to previous systems, [10][11][12][13][14] it was noted that the Z-cyclopropane was the major product. Subsequent experiments with other D 2 -symmetric chiral porphyrins with varied environments revealed a dramatic ligand effect (Table 1, entries 2-7).…”

“…Our first target was a-nitrodiazoacetates (NDAs), [9] as the resulting cyclopropanes have been demonstrated to be valuable precursors for a number of useful compounds, including the synthetically and biologically important cyclopropane aamino acids and aminocyclopropanes (Scheme 1). [10] Among several previous efforts towards metal-catalyzed cyclopropanation with NDA, [10][11][12][13] it is notable that Charette et al conducted a systematic evaluation of the reaction by employing various Rh-and Cu-based chiral catalysts.…”

Novel Liquid Crystalline Compounds Containing Bicyclo[3.1.0]hexane Core Units

“…Dirhodium tetraoctanoate catalyzed cyclopropanation of these 4-arylcyclopentenes 17 with tert-butyl diazoacetate [19] led, in spite of the bulky substituent on the diazoacetate and the bulky catalyst, only to a moderate excess of the desired exo,exo-diastereomers exo,exo-18, which were isolated in yields of 39Ϫ48% after crude chromatographic separation followed by recrystallization from methanol (Scheme 2).…”

Ring Opening of Donor–Acceptor Cyclopropanes with N-Nucleo­philes

“…The nucleophilic ring opening of 21 with diethylamine and esters of amino acids was performed under similar conditions (Scheme 9). 68 O'Bannon and Dailey researched a similar reaction for DA cyclopropane 23, 69 proving this compound to be more reactive towards aniline in comparison with 21. Full conversion of 23 into acyclic product 24 occurred in 15 hours under identical conditions (Scheme 10).…”

“…67,69 For instance, it was established that the ring in 1-nitro-2-phenylcyclopropane-1-carboxylate 50а was opened by aniline upon continuous heating at 90 °С, while the introduction of nickel(II) perchlorate hexahydrate as a catalyst allowed this reaction to complete at room temperature at an even higher rate (Scheme 20). The efficiency of the suggested technique was demonstrated by employing a series of 2-aryl-and 2-vinyl-substituted 1-nitrocyclopropane-1-carboxylates 50a-d together with derivatives of aniline and secondary cyclic amines as nucleophiles; consequently, α-nitro-γ-aminobutanoates 51 were obtained in good yields.…”