Total synthesis of panicein A₂

• Lili Yeung,
• Lisa I. Pilkington,
• Melissa M. Cadelis,
• Brent R. Copp and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 1991–1996, doi:10.3762/bjoc.11.215

• cytotoxicity against a number of tumour cell lines. Keywords: modified Claisen rearrangement; sesquiterpene; chromenol; total synthesis; Introduction The panicein family is an unusual family of natural products, which generally consist of an aromatic sesquiterpene group linked to a quinone (as seen in

• its deacetylation product 20. The direct conversion of deacetylated product 20 to panicein A2 (5) through a modified Claisen rearrangement [19][20] was then attempted. Unfortunately, after heating 20 in toluene for 48 hours, no desired product 5 was obtained, with a complex mixture of compounds

• sesquiterpine panicein A2 (5) has been achieved. This synthesis hinges on key steps involving the addition of phenol 16 to carbonate 18 to provide propargyl ether 8 which was then cyclised through a modified Claisen rearrangement to ultimately give the desired cyclic structure of 5. The correlation of