“…21 was prepared in three steps according to literature procedures and isolated as a colorless oil (7.4 g, 56% yield from 20 ). − 1 H NMR (CDCl 3 , 500 MHz): δ 5.60 (s, 1H), 3.74 (s, 2H), 2.00 (s, 2H), 1.74 (s, 3H), 1.66–1.58 (m, 2H), 1.33 (s, 1H), 1.19 (dt, J = 8.7, 4.0 Hz, 1H), 1.02 (s, 3H), 0.89 (s, 3H). Enantiomeric excess (90% ee) was determined by chiral HPLC analysis of the corresponding benzoyl ester of cyclogeraniol 9 .…”