Claisen rearrangement amino

Alkylation of 3-methyl-4-phenylisoxazolin-5-one with allyl bromide gave a mixture of N- and C(4)- alkylation in a 2 1 ratio. Heating the mixture changed the ratio to 1 99 and this conversion is believed to take place by an amino-Claisen rearrangement (Scheme 91) (69TL543). 

A thio-Claisen rearrangement174 was used for the regioselective synthesis of thiopyrano[2,3-b]pyran-2-ones and thieno[2,3-b]pyran-2-ones (Eq. 12.76). A convenient method for the aromatic amino-Claisen rearrangement of N-(l,l-disubstituted-allyl)anilines led to the 2-allylanilines being produced cleanly and in high yield by using a catalytic amount of p-toluenesulfonic acid in acetonitrile/water (Eq. 12.77).175... 

An approach in constructing the basic reserpine skeleton via the amino Claisen rearrangement of zwitterionic vinylisoquinuclidenes has been investigated (256, 257). 

Some other ring expansions involving the intramolecular amino Claisen rearrangement of vinylarylaziridine [ 123], the Diels-Alder reaction of indoles with acetylene derivative [124-127] and the dibromocarbene insertion into quinoline enol ethers [ 128] have been used to prepare 1-benzazepines. On the other hand, treatment of 3-chloro-3-phenyl-l,2,3,4,5,6-hexahydro-l-benz-azocin-2-ones with piperidine causes a ring contraction to give 2-phenyl-2-(l-piperidinylcarbonyl)-2,3,4,5-tetrahydro-l//-l-bcnzazepines in an excellent yield [23]. 

In a variation of this method, a dimethylamine adduct can be used in the same way as the methanol adduct described previously [Eq. (20)]. Nickel(II) and palladium(II) complexes with allyl-substituted NHCs are accessible by this route. These compounds cannot be prepared by the cleavage of an electron-rich olefin vide infra) because of an amino Claisen rearrangement of the tetramino-substituted olefin. However, [(NHC)M(CO)4] (M = Cr or Mo) were accessible via cleavage of electron-rich olefins with [M(CO)6] as the precursors but for the very same NHC. ... 

Thermally promoted Claisen rearrangement of simple allyloxypyrimidines is difficult to effect, but is more common with quinazolines where it has been used to prepare allyl derivatives substituted in the carbocyclic ring < 1996HC(55) 1 >. An attempted amino-Claisen rearrangement of a 4-allylaminopyrimidine was unsuccessful <2005AJC368>. 

The synthetic power of one-pot sequential reactions was demonstrated through an elegant route involving an amino-Claisen rearrangement, then intramolecular 1,3-dipolar cycloaddition, and finally reductive N-O bond cleavage to afford Ar-4-hydroxy-2-aryl-2,3,4,5-tetrahydro-l(l//)-benzazepines <2006SL2275>. 

The acid-catalyzed, amino-Claisen rearrangement of substituted A-vinyliso-quinuclidenes such as 40 and 41 (Scheme 1) served as the foundation of a novel entry to the molecular framework of lycorine (105). Thus, y-alkylation of the thermodynamic dienolate generated from 40, which was readily available from the Diels—Alder adduct 39, provided 41. Subsequent thermolysis of 41 for 24 hr... 

Amino-Claisen rearrangement of propargylamino-cyclohexenone and cyclopentenone is reported to proceed with ring closure to quinoline and pyridine derivatives (equation 82). The isomeric 2-propynylenaminone gave an indolone in good yield118 (equation 83). 

Although most catalysts for the various rearrangements are complexes of the late transition metals, TiCLi catalyzes the amino-Claisen rearrangement shown in equation (39). In this case, the thermal rearrangement gives identical prodnct yields. 

A third alternative may also be conceived, if for a moment one disregards all the nonparticipant atoms in compound IV. What is left is just an allyl-vinyl amine, a molecular combination reminiscent of what is necessary to perform a Claisen-type rearrangement (see Problem 19). Application of this rationale to intermediate IV would lead to cis structure III in a smooth, concerted fashion. This transformation is known in the literature as the amino-Claisen rearrange-... 

It will be instructive to comment briefly on the outcome of compound XIV, whose difference with respect to intermediate IV is the nonquatemization of the amine portion. Although the result of its exposure to II is the same in that tricyclic compound XVIII is produced, the amino-Claisen rearrangement cannot account for this process, since the protonation that would be expected to occur at nitrogen, thereby triggering the concerted transformation, surprisingly takes place instead on the oxygen atom of the carbonyl function (see Scheme... 

Beside the simple allylic N C transformation, which allows an allylation in the a-position of aldehydes avoiding completely the problem of 0- versus C-alkylation (Scheme 74), the amino-Claisen rearrangement seems especially suited for effecting asymmetric induction by employing optically active amine systems. ... 

With a chiral auxiliary in (42) such as 1-phenylethylamine (R = CHMePh), the diastereomeric excess in the reaction is low (de < 30%) and only improves somewhat when TiCU catalysis is used to lower the temperature and simultaneous 1,4- and l,S-asymmetric induction is attempted. A more promising approach was found in the amino-Claisen rearrangement of IV-allylketene lV,(7-acetals (44), which are... 

However, the most typical transformation of A-allylanilines is the [3,3]-sigmatropic rearrangement, known as the amino-Claisen rearrangement (46 - 47 48) that has been described in many reviews67-70 (equation 20). This process is sometimes also called the aza-Claisen rearrangement 71 as well as the aromatic aza-Cope rearrangement 72. 

In contrast to the well-known thermal Claisen rearrangement that enjoyed widespread application in organic synthesis73, the amino-Claisen rearrangement has received until recently much less attention. This may be due to some limitations such as the relatively low yields, the more drastic reaction conditions as well as the concomitant tendency... 

The products of the amino-Claisen rearrangement can in turn be involved in further isomerizations such as an aromatic di-rr-methane (ADPM) rearrangement98. Another noteworthy rearrangement is that occurring by treatment of V-allylaniline 58 with tert-butyllithium to give V-(2-methylene-4-pentenyl)aniline 60 via a vinyllithium derivative 59 (so-called 6-endo intramolecular carbometallation)99 (equation 24). 

The amino-Claisen rearrangement of compound 121 to compounds 123 and 86 has also been reported (Scheme 44). The intermediate compound 122 has been detected but not isolated (80JOC482). 

W-Alkyl-A -allyl enamines 128 (X = NR), like their carbon and oxygen counterparts 128 (X = CH2,0), can undergo [3,3]-sigmatropic rearrangement to form y,<5-unsaturated imines 129 (X = NR) (equation 27). This reaction has been defined as a 3-aza-Cope or the aliphatic amino-Claisen rearrangement. ... 

Following the isolation of (—)-S-N-nor-methylskytanthine (32) (36), Pombo-Villar and co-workers described a synthesis of the alkaloid in chiral form (Scheme 11) (193). A ketene amino-Claisen rearrangement (194) was... 

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