Theoretical study of hexaphosphabenzene and its valence isomers. Is cyclic P6 stable
Abstract Ab initio calculations show that the cyclic aromatic structure (hexaphosphabenzene) is a minimum on the P 6 potential energy surface, and is kinetically stable to its unimolecular destruction. In contrast to the N 6 analogue, hexaphosphabenzene lies very close in energy to its valence P 6 isomers. This interesting difference between P 6 and N 6 is analyzed in terms of energy components.
Zinc enolates derived from substituted 1-aryl-2,2-dibromoalkanones react with 3-acetyl-6-bromochromen-2-one to give 1a-acetyl-1-alkyl-1-aroyl-6-bromo-1a,7b-dihydro-1H-cyclopropa[c]chromen-2-ones as a single stereoisomer.