Synthesis of the Sesquiterpene Ketone Shyobunon and of its DiastereoisomersShyobunon (12) and 6‐epishyobunon (13) as well as their epimers 10 and 11 were synthetized in five steps from geranyl‐ (1) and nerylsenecionate (2), respectively. Ester enolate rearrangement [5] of 1 and 2 furnished the key intermediates 3 and 4 in high yield and in about 80% stereoselectivity [6] (Scheme 1). Conversion of the acid mixture 3/4 to the cyclohexanone derivatives 7 and 8 succeeded in 35–40% yield by means of cyclization of their acidchlorides with tin tetrachloride to the mixture of 5 and 6, followed by HCl elimination with diazabicyclononene (DBN) (Scheme 2). Selective reduction of 7 to 10 and 11, and 8 to 12 and 13 with triphenyltinhydride completed the synthesis.The relative configuration of 10 and 11 as well as of 12 and 13 were deduced from the 13C‐NMR. spectra (Scheme 4, Table 2). The structure of ‘epishyobunone’ is revised: it has the structure 13, and not 11 as described earlier [1]. This is discussed in connection with the rearrangement of acoragermacrone (16) [18] to shyobunone (12) and 6‐epishyobunone (13) (Scheme 5).