Additions and corrections

摘要

J. CHEM. SOC. PERKIN TRANS. I 1985 1249 Additions and Corrections Cardenolide Analogues. Part 12.l 13C N.m.r. of Semi-synthetic Glycosides and Side-chain Modified Genins By H. T. Andrew Cheung," Lindsay Brown, John Boutagy, and Richard Thomas J. Chem. SOC.,Perkin Trans I, 1981 1773. Page 1774, right-hand column, formulae (20H26): delete displayed formula and insert the following: HR20 I., 0R1 R3R20CH;,RPOR1 The Synthesis of Lignans and Related Structures using Quinodimethanes and Isobenzofurans: Approaches to the Podophyllins John Mann," Susan E. Piper, and Lilan K. P. Yeung J. Chem. SOC.,Perkin Trans I, 1984,2081. Following correspondence (P. Durst and J. L. Charlton, Tetrahedron Lett., 1984,25,5287) concerning our paper, we should like to make the following corrections.Further investigation of the cycloaddition of sulphone (13c) with (2)-dimethyl butenedioate (entry D in Table 1) has shown that this reaction is exquisitely sensitive to reaction conditions. If freshly synthesized dienophile is employed together with totally anhydrous solvent, the all-cis-cycloadduct is indeed formed. If, on the other hand, commercial dienophile is employed, or water is present, or the temperature remains in excess of 170 "Cfor the extended periods, the all-trans-cycloadduct (entry C in Table 1) is obtained. This reaction is thus not so reliable as the other cycloadditions cited. Page 2086, Table 2, column headed 'Other'; entry (C), delete first entry '3.5' and insert '3.7'; entry (D),delete second entry '3.86' and insert '3.68'. 0Copyright 1985 by The Royal Society of Chemistry