Skip to main content Accessibility help
×
Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-28T22:56:24.403Z Has data issue: false hasContentIssue false

4 - Synthetic Diels–Alder routes to rings B and C

Published online by Cambridge University Press:  07 September 2010

Get access

Summary

Additions to 1,4-naphthoquinones

1-Vinylcyclohexene, 195, has been reacted with 1,4-naphtho-quinone, 196, to give 1,2,3,4,6,6a,12a,12b-octahydroBAQ, 197, in high yield (Backer and Bij, 1943; Azerbaev, 1945), Scheme XXIV. On air oxidation 197 was converted into 1,2,3,4-tetrahydroBAQ, 198 (Fieser and Hershberg, 1937b), which was reduced to 1,2,3,4-tetrahydroBA. With the exception of two other examples (Inbasekaran et al., 1980; Carothers and Coffman, 1932), no further work with the use of vinylcyclohexenes in BA synthesis has been reported.

Rather, the addition of styrenes, 199, to 196, has been studied and well developed. When the reactions were carried out in refluxing toluene containing chloranil and trichloroacetic acid, the following nine BAQs, 200, were obtained:4-Br-, 1-, 2-, 3-, 4-Cl-, 4-F-, 4-methoxy-, 2-methyl-, and 1,4-dimethyl- (Manning et al., 1977). Subsequently, 3,4-dimethoxy- BAQ, 201, was synthesized (Manning and Wilbur, 1980) by a similar route. When 5-hydroxy-1,4-naphthoquinone, 202, and 5-methoxy-1,4- naphthoquinone, 203, were used, mixtures of 8-hydroxy- and 11-hydroxyBAQs, 204 and 206, and 8-methoxy- and 11-methoxyBAQs, 205 and 207, resulted (Manning, 1979). By the use of 6-hydroxy- and 6-methoxy-1,4-naphthoquinones, 208 and 209, there were obtained mixtures of 9-hydroxy- and 10-hydroxyBAQs, 210 and 212, and 9-methoxy- and 10-methoxyBAQs, 211 and 213, respectively (Manning, 1979; Manning et al., 1979; Manning, 1981). The conversion of many of the BAQs into BAs and 7,12-DMBAs by conventional methods has been described (Muschik et al., 1979). However, difficulties were encountered in the synthesis of BAs bearing the 1-methoxy group because of steric factors.

Type
Chapter
Information
Publisher: Cambridge University Press
Print publication year: 1988

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×