Bicyclo heptanol

Tetramethylcyclohexanes.—An improved method for the preparation of j3-cyclocitral in purer form has been described. The methylsulphonate of a-cyclogeraniol (188) forms the cyclopropane derivative (189) with calcium carbonate, and this rearranges to a bicyclo[3,l,l]heptanol (190) with methane-sulphonic acid. Bohlmann and Zdero have found that the angelic acid ester of... 

Epoxybicyclo[3.2.0]heptanols 1 undergo acid-catalyzed cyclobutyl-cyclopropylmethyl rearrangement to form the bicyclo[4.1.0]hexan-3-one system 1. The efficiency of this cationic rearrangement appears to be dependent on the nature of the substituent R . This phenomenon is interpreted by the substituent effect on the stability of the incipient cyclopropylmethyl cation. 

If the rearrangement was performed in the presence of a reducing agent, such as potassium tri- erf-butoxyaluminum hydride, the intermediate ketone could be reduced to a 2 1 mixture of (la,2oi,6 )- and (la,2j6,6/S)-bicyclo[4.1.0]heptanols 6, which provided the first examples of a /ran -bicyclo[4.1.0]heptane. 

A lipase-catalyzed kinetic resolution was described by Parve et al. (89). Bicyclo[3.2.0]heptanol esters were hydrolyzed in SCCO2 with the lipase from Humicola lanuginosa at 40°C and 200 bar. From the racemic ester in Eq. (12), a 59% isolated yield of the 1R,2S,3S,5R ester (67% e.e.) and a 3% yield of the 1S,2R,3R,5S alcohol (92% e.e.) were obtained after 100 h ... 

Parve O, Vallikivi I, Lahe L, Metsala A, Lille U, Tougu V, Vija H, Pehk T. Lipase-catalysed enantioselective hydrolysis of bicyclo[3.2.0]heptanol esters in supercritical carbon dioxide. Bioorg Med Chem Lett 1997 7 811-816. 

The technique of mass spectroscopy is of considerable value in the study of mechanism with compounds of known structure but it remains qf little value in the determination of structure of bridged compounds of unknown structure. Spectra have been recorded of bicyclo[2,2,l]heptanols, acetates of bicyclo[2,2,l]heptanols, trimethylstannylnorbomenes, nortricyclenes, adamantanes, and dimethanonaphthalenes. ... 

Methods of determination of the configuration of bicyclo[2,2,l]-heptanols have been reviewed. The platinum-catalysed oxidation of bicyclo-[2,2,l]heptanediols, whose n.m.r. spectra are discussed, gives ° a number of different diketones and hydroxy-ketones. The n.m.r. spectra of adducts of cyclopentadiene with a-methyl-P-acetylacrylic acid, and of dimers of substituted cyclopentadienes, are noted. 

Stereoselective copper(l)-catalyzed [2 -I- 2]-photocycloaddition of 1,6-heptadienols has been used as a key step in the synthesis of several natural products. The total synthesis of the sesquiterpenes a-panasinsene 47 and P-panasinsene 48 has been achieved by CuOTf catalyzed photocycloaddition of the dienol 43 as the key step (Scheme 15). The resulting bicyclo[3.2.0]heptanol 44 was then converted to the natural products through the ketone 46. It is noteworthy that direct access to the requisite intermediate 46 involving photoaddition of isobutylene to the enone 45 failed, illustrating the importance of the copper(l)-catalyzed photocycloaddition of 1,6-heptadienols. 

The bicyclo[3.2.0]heptanols obtained through this cycloaddition process can be exploited for the stereocontroUed synthesis of 1,2-disubstituted cyclobutanes. The concept is demonstrated by the synthesis of grandisol 53 (Scheme 16), the pheromone of the male cotton boU weevil Rosini et al. have described... 

Pasta et al. [63] Subtilisin bicyclo[3.2.0]heptanol esters Transesterification CO2 Batch... 

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