1- - amine cyclopentane

At low temperature a 1 1 adduct of thioacetic acid and an enamine could be prepared (709). The previously described reaction of aminomethylene ketones with hydrogen peroxide was extended to bisaminomethylene compounds. However, acylated cyclohexenamines led to cyclopentane-carboxamides (770), Trichloromethyl adducts of enamines and the rearranged amine derivatives were described in a further study (777). 

Scheldt and co-workers have also accessed enolate equivalents from enals to furnish cyclopentanes 236 asymmetrically. Formation of the enolate equivalent from enals 235 with the NHC, followed by an intramolecular Michael reaction and 0-acylation, gives the lactone products 236, which are readily opened by either alcohols or amines to generate functionalised cyclopentane derivatives 237 in excellent ee. 

We now consider 7V-methyl-2-(3-pyridyl)pyrrolidine (7), also known as the alkaloid nicotine. Parallelling our discussion of coniine, we find in Kharasch and Domalski the nearly century-old enthalpy of formation for the liquid of 39 kJmol-1. Is this value plausible With (liquid, tert/R, R1, R2) necessary to transform a tertiary amine into the corresponding hydrocarbon24, we would conclude that the enthalpy of formation of liquid l-methyl-2-(3-pyridyl)cyclopentane (8, R = 3-Py) is ca —50 kJmol-1. To estimate the last datum in another way, we assume that equation 10 is essentially thermoneutral. 

Rhodium(II) acetate catalyzes C—H insertion, olefin addition, heteroatom-H insertion, and ylide formation of a-diazocarbonyls via a rhodium carbenoid species (144—147). Intramolecular cyclopentane formation via C—H insertion occurs with retention of stereochemistry (143). Chiral rhodium (TT) carboxamides catalyze enantioselective cyclopropanation and intramolecular C—N insertions of CC-diazoketones (148). Other reactions catalyzed by rhodium complexes include double-bond migration (140), hydrogenation of aromatic aldehydes and ketones to hydrocarbons (150), homologation of esters (151), carbonylation of formaldehyde (152) and amines (140), reductive carbonylation of dimethyl ether or methyl acetate to 1,1-diacetoxy ethane (153), decarbonylation of aldehydes (140), water gas shift reaction (69,154), C—C skeletal rearrangements (132,140), oxidation of olefins to ketones (155) and aldehydes (156), and oxidation of substituted anthracenes to anthraquinones (157). Rhodium-catalyzed hydrosilation of olefins, alkynes, carbonyls, alcohols, and imines is facile and may also be accomplished enantioselectively (140). Rhodium complexes are moderately active alkene and alkyne polymerization catalysts (140). In some cases polymer-supported versions of homogeneous rhodium catalysts have improved activity, compared to their homogenous counterparts. This is the case for the conversion of alkenes direcdy to alcohols under oxo conditions by rhodium—amine polymer catalysts... 

Cyclization to a morpholinolactone (59) occurs in the hydrolysis reaction of the di-A-hydroxylethylated compound (60). Compound (59) is rapidly hydrolysed by water to (61) but in file presence of equimolar amounts of amines (RNH2) or ammo acid derivatives (62) forms.56 A novel reaction of cyclic 2-diazo-l,3-dicarbonyl compounds (63) with lactones (64) affords the products (65) in the presence of rhodium acetate, Rh2(OAc)4.57 Lewis acid-promoted intramolecular additions of allylsilanes to lilac tones gave substituted cyclopentanes.58 A proposed transition state guided efforts to improve the stereoselectivity of the reaction. The reaction of a series of /1-lactone derivatives, such as (66)-(68), has been studied and they have been ling cleaved the reaction outcome is both Lewis acid and structure dependent.59... 

In the Woodward synthesis of prostaglandin (621, intermediate 172 formed in situ from the corresponding amine was smoothly transformed into bicyclic aldehyde 173. Seebach and co-workers (63) have also observed several stereospecific rearrangements using the same reaction. For example, diazotization of amine 174 gave specifically the cis-cyclopentane 175 which was then epimerized into the more stable trans-cyclopentane 176. 

Methylphenylgermylene was generated by retrocycloaddition from the germana-cyclopentane analogue.107 The germylene was detected directly and by analysis of reaction products. Rate constants for the reactions with amines, acids, silanes, stan-nanes, oxygen, and unsaturated carbon-carbon bonds were given. 

Parry, R.J. et al. Investigations of Aristeromycin Biosynthesis Evidence for the Intermediacy of a 2a,3a-Dihydroxy-4j3-(hydroxy-methyl)cyclopentane-1 /3-amine. 2.4 1991 [167]... 

Although only a few hydrocarbons have been studied it appears that most of them react with OH with a rate constant of ca. 109 M-1 s 1. Methane is about 4 times less reactive than this value, and cyclopentane and cyclohexane about 5 times more reactive. Alcohols, amines, ethers, and many esters also fall in the same range. Carboxylic acids and carbonyl compounds seems to be to a certain degree less reactive. Lower reactivity is also found for the protonated forms of amines and amino acids. Direct reaction of OH with the substituent is usually unimportant except for a few cases such as thiols, where H is easily abstracted from the SH, or nitroso com-... 

Pyridine, 2-methylpyridine, pyrimidine, pyrrole, imidazole, indole, and purine are aromatic. 19.3. (a) pentan-2-amine (b) A-methylbutan-2-amine (c) m-aminophenol (d) 3-methylpyrrole (e) /ram-cyclopentane -1,2-diamine (f) c -3-aminocyclohexanecarbaldehyde. 19.4. (a) resolvable (chiral carbons) (b) not resolvable (N inverts) (c) symmetric ... 

In a more recent study, the enamide photocyclization with very similar photosubstrates was examined in the presence of chiral amino alcohols and chiral amines as asymmetric inductors [47]. The achieved enantioselectivities are in the same range as the ones reported by Ninomiya and Naito, but in this approach the asymmetric induction was more effective for the cis products. In cyclopentane at — 40°C, 0.1 equivalents of the most effective inductor, (— )-ephedrine (entity, gave the cis cyclization products with up to 37% ee and the trans products with only 2% ee. The role of the chiral inductor as a Br0nsted acid was supported by flash photolysis experiments. The presence of the chiral amino alcohol led to an increase in the rate of disappearance of a transient that was assigned to the primary cyclization intermediate of type 29, i.e., the chiral inductor accelerates the protonation/deprotonation sequence that reestablishes the aromatic ring. 

Cyclopentan 2-Hydroxy-l-propyla-mino- E16d, 1125 (Oxiran 4-Amin)... 

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