A formal [3+3]-annulation-based approach to pancratistatins: total synthesis of ()-7-deoxy-pancratistatin and its 2-epi and 2,4-diepi analoguesElectronic supplementary information (ESI) available: Experimental procedures for 20ab, 22ab, 1,2-cis-23, 2628, 33 and 17, including nOe data for 1,2-cis-23 and X-ray data for 1,2-cis-22a; NMR spectra for compounds 17, 15a, 15b, 6, 5, 20a, 20b, 1,2-trans-22a, 1,2-cis-22a, 1,2-cis-23, 24a, 24b, 14a, 25, 2, 27, 28, 30, 31, 16a, 16b, 32, 7 and 33; and some a

A full account is given for the total synthesis and the cytotoxic activity against the human lung tumoral cell line NCI-H460 of ()-7-deoxy-pancratistatin and its 2- epi - and 2,4-di epi - unnatural analogues. ()-7-Deoxy-pancratistatin and its 2- epi - and 2,4-di epi - analogues are prepared from a total of four commercially-available fragments.