... 91 H. Staab, B. Meissner, Liebigs Ann. Chem. 753 (1971) 80. lo) DE Pearson, M. G. Frazer, V. S. Frazer, L. C. Washburne, Synthesis 1976, 621. ''I P. Paetzold, A. Richter, T. Thijssen, S. Wiirtenberg, Chem. Ber. 112 (1979) 3811. [320/87] Chem. Ber. 121, 809-810 (1988)