A practical synthesis of isomerically pure 1,10-difunctionalized derivatives of the [closo-1-CB9H10] anion

Bryan Ringstrand; Andrzej Balinski; Andreas Franken; Piotr Kaszynski

doi:10.1021/ic051311j

A practical synthesis of isomerically pure 1,10-difunctionalized derivatives of the [closo-1-CB9H10] anion

Inorg Chem. 2005 Dec 12;44(25):9561-6. doi: 10.1021/ic051311j.

Authors

Bryan Ringstrand¹, Andrzej Balinski, Andreas Franken, Piotr Kaszynski

Affiliation

¹ Organic Materials Research Group, Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA.

PMID: 16323945
DOI: 10.1021/ic051311j

Abstract

The isomer-free [closo-1-CB9H(8)-1-COOH-10-I]- anion was prepared in four steps and 10% overall yield from B10H14. The key step is the skeletal isomerization of the [closo-2-CB9H8-2-COOH-7-I]- anion to a mixture of the 10- and 6-iodo derivatives of [closo-1-CB9H(9)-1-COOH]- formed in up to a 3:1 ratio. The carboxylic acid 4 was converted to the amine [closo-1-CB9H(8)-1-NH(2)-10-I]- using the Curtius reaction. The relative thermodynamic stability of each product was calculated at the DFT and MP2 levels of theory. The regioselectivity of electrophilic substitution in [closo-CB9H10]- derivatives was briefly investigated using the NBO population analysis of the MP2 wave function.