1. Contribution from the Institute for Fundamental Research of Organic Chemistry (IFOC) and Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki 6-10-1, Fukuoka 812, Japan, and Fujitsu Kyushu System Engineering (FQS) Limited, Momochihama 2-2-1, Sawara-ku, Fukuoka 814, Japan