Cyclopentyl acetate

The reaction of small ring hydrocarbons with acids has been extensively studied. Although cyclopropane does not react with acetic acid, bicyclo[2.1.0]pentane (20) reacts rapidly to give cyclopentyl acetate. On the other hand, bicyclo[2.2.0]hexane (21) does not react. Other small ring hydrocarbons that react rapidly with acetic... 

Compensation has recently been observed in the dissociation of bisulfite addition compounds (Blackadder and Hinshelwood, 1958), in the ionization of phenols (Chen and Laidler, 1962), in the alkaline hydrolysis of certain cyclopentyl acetates (Bruice and Fife, 1962), and in the acylation of aromatic amines (Venkataraman and Hinshelwood, 1960). 

We already know from part (a) how to convert / runs-2-methy I c yc I ope n tanol to ris-2-methyl-cyclopentyl acetate. So all that is really necessary is to design a synthesis of frans-2-methyl-cyclopentanol. Therefore,... 

Hydroboration-oxidation converts 1-methylcyclopentene to the desired alcohol by anti-Markovnikov syn hydration of the double bond. The resulting alcohol is then converted to its p-toluenesulfonate ester and treated with acetate ion as in part (a) to give m-2-methyl-cyclopentyl acetate. 

The stereoselectivity of the C-methylation of oxolanyl and cyclopentyl acetate eno-lates (11, X = O, CH2) has been investigated (Scheme 3).26 The methylation has proceeded re -selectively, although with very different degrees of selectivity (re si (g) from 62 38 to 96 4). The most important stereodirecting effect was a steric one exerted by the 5-phenethyl substituent, and this steric effect was strongly increased by the stereodirecting effect of a 3-OMe group. 

Preparation of frans-(3,4-dimethyl-l-nitromethyl-cyclopentyl)-acetic acid ethyl ester... 

Preparation of ( )-(traw.y)-( l-aniinomethyl-3,4-dimethyl-cyclopentyl)-acetic acid hydrochloride... 

For strained bicyclic molecules such as bicyclo[2.1.0]pentane calculations suggest a strong preference for protonation at a bridgehead carbonThis prediction seems to be consistent with experimental results in which bicyclo[2.1.0]pentane-endo-5-d is solvolyzed in acetic acid containing p-toluenesulfonic acid to give cyclopentyl acetates and tosylates (as well as some cyclopentene) in which distribution of the deuterium among all possible sites could be quantified. Isotope effects and label distributions were found to be consistent with the initial formation of a C(l)-protonated bicyclo[2.1.0]pentane. 

F.16) Cyclopentanol, acetate, cyclopentyl acetate 1933-05-11 Identified by Cros et al. (1980) in a headspace of roasted coffee. 

Two Pd-catalyzed cyclizations were used for the enantioselective synthesis of (—)-cephalotoxine [109]. One-pot Pd-catalyzed domino reactions, namely intramolecular allylation of amine and HR of 256, seem to be the best path for the desired synthesis. However, attempted direct conversion of 256 to 258 with the Herrmaim complex was unsuccessful. Then selective intramolecular aminoallylation with the chiral cyclopentyl acetate occurred smoothly to give the Spiro amine 257 in 88 % yield when Pd(PPh3)4 and TMG (tetramethylguanidine) as a base were used. The cyclization proceeded with retention of stereochemistry without racemization. The next HR reaction of 257 gave the seven-membered compound 258 in 81% yield under Jeffery s conditions using the Herrmann complex as a catalyst. No transformation of 257 to 258 occurred when Pd(PPh3)4 was used. The results show that the best catalysts for the allylation and HR are different. 

Carboxymethyl-cyclopentyl) acetic acid. See 3,3-Tetramethylene glutaric acid (Carboxymethyl) decyidimethylammonium hydroxide N-(Carboxymethyl)-N,N-dimethyl-1-decanaminium hydroxide, inner salt. See Decyl betaine... 

Synonyms Cyclopentaneacetic acid, 3-oxo-2-(2-pentenyl)-, methyl ester Jasmoneige Methyl epi-jasmonate Methyl 2-pent-3-enyl-3-oxo-1-cyclopentyl acetate 3-Oxo-2-(2-pentenyl) cyclopentaneacetic acid, methyl ester 2-Pentenylcyclopentanone-3-acetic acid, methyl ester Empiricai C13H20O3... 

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