r 1 represents a substituted methyl or methylene group the thermal rearrangement is carried out under anhydrous conditions the invention will now be described in further detail by way of the following examples wherein the abbreviations have the usual meaning in the art the temperatures are indicated in degrees centigrade u00b0 c the nmr spectral data were recorded with a 360 mhz machine in cdcl 3 the chemical displacement u03b4 are indicated in ppm with respect to the tms as standard the coupling constant j are expressed in hz and all the abbreviations have the usual meaning in the art a solution of cyclopentenone 1 23 g 15 mmol pentanal 1 94 g 22 5 mmol rac 1 1 u2032 bi 2 naphthol 429 mg 1 5 mmol and tributyl phosphine 606 mg 3 mmol in dry thf 12 ml was stirred at 20 u00b0 c under argon for 3 hours the solution was then passed through a short column of sio 2 cyclohexane et 2 o 6 4 to obtain the pure title compound in 92 yield ir 3412 2925 2858 1682 1630 1440 ms 168 m 0 150 18 135 10 121 12 111 100 83 19 55 16 1 h nmr 0 92 t j 7 3h 1 33 m 4h 1 43 s 1oh 1 68 m 2h 2 45 m 2h 2 60 m 2h 4 46 t j 7 1h 7 49 t j 1 5 1h 13 c nmr 14 0 q 22 6 t 26 6 t 27 6 t 35 3 t 35 6 t 67 7 d 148 0 s 158 1 d 210 4 s a mixture of.