R. Rodrigo

Hydroxyacetals, phthalans, and isobenzofurans therefrom

National Research Council of Canada NRC Research Press Electronic Journals 1. Rights NRC Research Press grants the Subscriber and authorized users at the Subscribers institution the right to access the electronic version of those NRC Research Press journal volumes for which the Subscriber maintains an electronic subscription. It is a condition of receiving access to the electronic journals that any person who violates either the copyright or the restrictions on distribution, or who condones such acts, may be deprived of future access, including access to back issues, without compensation or refund, while NRC retains the further right to any legal remedies that may be available. 2. Authorized Users Authorized users are defined as employees, faculty and students of the Subscriber who access the electronic journals from a computer terminal within the range of the Internet Protocol (IP) addresses provided by the Subscriber at time of purchase. Access to the electronic journal by persons other than those listed above is restricted to the use of a computer terminal located in a Subscriber library. 3. Authorized Site An authorized site, is a contiguous campus community or buildings which are located within the same city and reporting to the same administrative body. Affiliated locations outside of the defined site are considered to be separate sites. Within a multi-company complex or building, each company is considered to be a separate site. 4. Usage Restrictions The Subscriber and authorized users may view, print and download single copies of articles or other content for personal use. The Subscriber and authorized users may not make copies for general distribution, for advertising or other promotional purposes, for creating new collective works, or for any resale purpose such as document delivery. For such copying, separate agreements must be made with the copyright owner. The Subscriber will notify all authorized users of permitted and prohibited use, and the Subscriber will take any corrective action necessary against authorized users who contravene these conditions. 5. Copyright No part of this publication may be reproduced, stored, or transmitted in any form or by any means, without the written permission of the publisher, except as stated below. The National Research Council of Canada grants premission to individuals to download or print single copies of articles for personal use. Any person may reproduce short excerpts from articles in the journals for any purpose that respects the moral rights of authors, provided that the source is fully acknowledged. As a courtesy, the consent of authors of such material should be obtained directly from the author. Authorization to reproduce items for other than personal use, as stated above, is granted by the National Research Council of Canada provided that the copyright fee of

An exceptional 5-endo–trig reversal; a convergent synthesis of daunomycinone

7.00 per copy is paid directly to the Copyright Clearance Centre (CCC) Transactional Reporting Service, 222 Rosewood Drive, Danvers, MA 01923, U.S.A. /Tel: 508-750-8400 / Fax: 508-750-4744. The above permission does not extend to other kinds of copying, such as copying for general distribution, for advertising, or promotional purposes, for creating new collective works, or for resale. For such copying, arrangements must be made with the publisher, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada. For British Crown copyright articles, permission for other than private research, study or in-house use must be obtained from The Copyright Unit, St. Clemens House, 2-16 Colegate, Norwich, England NR3 1BQ. 6. Warranty NRC accepts no responsibility for statements or opinions expressed by a contributor and consequently accepts no liability for damages that may result from the Subscribers use of the NRC journals. Acceptance of an advertisement, announcement, or other material does not imply endorsement by either the Journal Editors or NRC. The Controller of Her Majestys Stationery Office and authoring Departments accept no responsability for the accuracy of any recipe, formula or instruction contained within any British Crown copyright article or any other material in this publication. I Agree

Progress towards viridin: synthesis of the pentacyclic furanosteroid ring system via o-benzoquinonoid cycloadditions

National Research Council of Canada NRC Research Press Electronic Journals 1. Rights NRC Research Press grants the Subscriber and authorized users at the Subscribers institution the right to access the electronic version of those NRC Research Press journal volumes for which the Subscriber maintains an electronic subscription. It is a condition of receiving access to the electronic journals that any person who violates either the copyright or the restrictions on distribution, or who condones such acts, may be deprived of future access, including access to back issues, without compensation or refund, while NRC retains the further right to any legal remedies that may be available. 2. Authorized Users Authorized users are defined as employees, faculty and students of the Subscriber who access the electronic journals from a computer terminal within the range of the Internet Protocol (IP) addresses provided by the Subscriber at time of purchase. Access to the electronic journal by persons other than those listed above is restricted to the use of a computer terminal located in a Subscriber library. 3. Authorized Site An authorized site, is a contiguous campus community or buildings which are located within the same city and reporting to the same administrative body. Affiliated locations outside of the defined site are considered to be separate sites. Within a multi-company complex or building, each company is considered to be a separate site. 4. Usage Restrictions The Subscriber and authorized users may view, print and download single copies of articles or other content for personal use. The Subscriber and authorized users may not make copies for general distribution, for advertising or other promotional purposes, for creating new collective works, or for any resale purpose such as document delivery. For such copying, separate agreements must be made with the copyright owner. The Subscriber will notify all authorized users of permitted and prohibited use, and the Subscriber will take any corrective action necessary against authorized users who contravene these conditions. 5. Copyright No part of this publication may be reproduced, stored, or transmitted in any form or by any means, without the written permission of the publisher, except as stated below. The National Research Council of Canada grants premission to individuals to download or print single copies of articles for personal use. Any person may reproduce short excerpts from articles in the journals for any purpose that respects the moral rights of authors, provided that the source is fully acknowledged. As a courtesy, the consent of authors of such material should be obtained directly from the author. Authorization to reproduce items for other than personal use, as stated above, is granted by the National Research Council of Canada provided that the copyright fee of

Potential isobenzofurans: their use in the synthesis of naturally occurring 1-arylnaphthalide lignans

7.00 per copy is paid directly to the Copyright Clearance Centre (CCC) Transactional Reporting Service, 222 Rosewood Drive, Danvers, MA 01923, U.S.A. /Tel: 508-750-8400 / Fax: 508-750-4744. The above permission does not extend to other kinds of copying, such as copying for general distribution, for advertising, or promotional purposes, for creating new collective works, or for resale. For such copying, arrangements must be made with the publisher, National Research Council of Canada, Ottawa, ON K1A 0R6, Canada. For British Crown copyright articles, permission for other than private research, study or in-house use must be obtained from The Copyright Unit, St. Clemens House, 2-16 Colegate, Norwich, England NR3 1BQ. 6. Warranty NRC accepts no responsibility for statements or opinions expressed by a contributor and consequently accepts no liability for damages that may result from the Subscribers use of the NRC journals. Acceptance of an advertisement, announcement, or other material does not imply endorsement by either the Journal Editors or NRC. The Controller of Her Majestys Stationery Office and authoring Departments accept no responsability for the accuracy of any recipe, formula or instruction contained within any British Crown copyright article or any other material in this publication. I Agree

Progress in the chemistry of isobenzofurans; applications to the synthesis of natural products and polyaromatic hydrocarbons

The pentacyclic ring system of viridin is synthesised in nine steps from 4-methylguaicol by means of successive cycloadditions involving o-benzoquinonoid intermediates generated in situ.

Shikimic acids from furan; methods of stereocontrolled access to 3,4,5-trioxygenated cyclohexenes

A three-step synthesis of seven lignans by means of a Diels–Alder reaction followed by selective borane reduction of an aromatic ester is described.