Electronic supplementary information (ESI) available: characterisation data for compounds 7, 9 and 16. See http://www.rsc.org/suppdata/cc/b0/b001253j/
Electronic supplementary information (ESI) available: synthesis and spectroscopic data for 4b, 5g, 6b and 7b. See http://www.rsc.org/suppdata/cc/b1/b100355k/