Oxidative pyrrolidine derivative

Carbonylation of the tetrasubstituted bispropargyiic amine 23 using PdCP and thiourea under mild conditions affords the carboxylated pyrrolidine derivatives 24a and b in good yields. Thiourea is regarded as effective for the oxidative carbonylation of alkynes, but no oxidative carbonylation was observed in this case[21]. 

The (2pyrrolidine derivative 843 can catalyze a hetero Diels-Alder (hDA) reaction between aldehydes and enones 844 to form dihydropyranols 845, PCC oxidation of which affords tf //-3,4-dihydropyran-2-ones 846 in good yield and enantioselectivity (Scheme 238) <2003AGE1498>. 

The palladium-catalyzed [3 + 2] cycloaddition of vinylic oxirane 20a [42] and aziridine 20b [39] with the activated olefin 4a for the formation of five membered cyclic ether 21a and pyrrolidine derivative 21b has also been reported in our laboratories. The mechanistic issue is very much similar to that discussed in Scheme 9. Pd(0) catalyst added oxidatively to 20 to produce the 7r-allylpalladium complex 22. The Michael addition of a hetero nucleophile in 22 to the activated olefin 4a gives 23 which undergoes intramolecular nucleophilic attack on the inner 7r-allylic carbon atom to give the cy-clized products 21 and Pd(0) species is generated (Scheme 10). Similarly, the palladium-catalyzed [3 + 2] cycloaddition of vinylic oxirane 20a with the N-losylimincs 24 is also known (Scheme 11) [43]. Intermolecular cycloaddition of vinyl epoxides and aziridines with the heterocumulenes such as isocyanates, carbodiimides and isothiocyanates is also known [44,45]. Alper et al. reported the regio- and enatioselective formation of the thiaolidine, oxathiolane, and dithiolane derivatives by the palladium-catalyzed cyclization reaction of 2-vinylthiirane with heterocumulenes [46]. 

Simple amines in the presence of Oxone oxidize alkenes to oxiranes. For example, Oxone, pyridine, and a 2-pyrrolidine derivative in a medium of aqueous acetonitrile selectively converts the triene in Equation (72) to a single epoxide. This process also proceeds using noncyclic alkenes. The mechanism is believed to proceed via a single-electron transfer (SET) process involving radical cation intermediates <2000JA8317>. 

In 1997, the same group disclosed an example of highly enantioselective C—H bond oxidation reactions. As shown in Scheme 1.61, conformationally fixed 3-oxa-bicycle[3.3.0]-octane 156 was oxidized at the a position under the catalysis of the Mn catalyst C25 ligated by a BINOL-derived salen ligand. Subsequently, the same group further expanded the scope to a meso-pyrrolidine derivative (up to 76% ee) and a meso-tetrahydrofuran derivative (up to 90% ee). Later,... 

A computational study of the two possible mechanisms for the asymmetric epoxidation of conjugated aldehydes with H2O2, catalysed by chiral pyrrolidine derivatives lacking proton donor groups, indicates that the more probable route is via formation of an iminium intermediate rather than the general base-catalysed mechanism. The oxidant H2O2 acts as a co-catalyst in the initial formation of the iminium species. The epoxide... 

N-Alkyl Derivatives. - Isomeric mixtures of AT-(hexosid-2-yl)-pyrrolidine derivatives, e.g. 98, were formed along with some AT-demethylated amine 99 on treatment of the AT-oxide 100 with lithium diisopropylamide in the presence of various dienes, e.g. 2-methyl-1,4-butadiene. The synthesis of carbocyclic analogues of a mannose trisaccharide, linked via nitrogen atoms, is covered in Chapter 18. 

The catalytic cycle of this reaction has been shown in Scheme 40.5. At first, the Pd(0) catalyst reacts with the aryl bromide to generate the Pd(Ar)Br complex 19 via a simple oxidative addition. Complex 19 reacts with the amino alkene in the presence of NaO Bu base to generate the Pd (Ar)amido complex 21, which after subsequent alkene insertion into the Pd N bond followed by C C bondforming reductive elimination leads to the formation of substimted pyrrolidine derivative 23 along with the regeneration of the Pd(0). 

In 1931 Winterfeld and Kneuer, as a result of their observation that jS-lupinane can be obtained from lupanine, and the formation of 2-methyl-pyrrolidine by the oxidation of sparteine, combined these two features in a partial formula (II) for lupanine, which could be developed in various ways depending on the mode of attachment of the methylpyrrolidine residue. In view, however, of Ing s demonstration of the relationship of anagyrine, CJ5H20ON2, to Z-lupanine, CJ5H24ON2, and d-sparteine, C15H28N2, it was elearly neeessary to consider formul for lupanine derivable from the two alternati-ves, which Ing had proposed for anagyrine and which are shown below as (III) and (IV) with the formul for lupanine derived from them (V) by Ing and (VI) by Clemo and Raper. Sparteine would be represented by (V) or (VI) with the change CO CH2. 

Alicyclic hydroxamic acids undergo several specific oxidative cleavage reactions which may be of diagnostic or preparative value. In the pyrrolidine series compounds of type 66 have been oxidized with sodium hypobromite or with periodates to give y-nitroso acids (113). Ozonolysis gives the corresponding y-nitro acids. The related cyclic aldonitrone.s are also oxidized by periodate to nitroso acids, presumably via the hydroxamic acids.This periodate fission was used in the complex degradation of J -nitrones derived from aconitine. 

A family of interesting polycychc systems 106 related to pyrrolidines was obtained in a one-pot double intermolecular 1,3-dipolar cycloaddition, irradiating derivatives of o-allyl-sahcylaldehydes with microwaves in toluene for 10 min in presence of the TEA salt of glycine esters [71]. A very similar approach was previously proposed by Bashiardes and co-workers to obtain a one-pot multicomponent synthesis of benzopyrano-pyrrolidines 107 and pyrrole products 108 (Scheme 37). The latter cycloadducts were obtained when o-propargylic benzaldehydes were utihzed instead of o-allyhc benzalde-hydes, followed by in situ oxidation [72]. 

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