1. Contribution from the Department of Organic Chemistry and The Lise Meitner Minerva Center for Computational Chemistry, Safra Campus, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel, Department of Chemistry, University of Alberta, Edmonton, AB T6G2G2, Canada, Merkert Chemistry Center, Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467-3860, and Organic Chemistry, Technical University of Braunschweig, Hagenring 30 D-38106 Braunschweig, Germany