(5<i>R</i>^*, 9<i>S</i>^*)‐ and (5<i>R</i>^*, 9<i>R</i>^*)‐2,2,9‐Trimethyl‐1,6‐dioxaspiro[4.4]non‐3‐ene and their Dihydro Derivatives as New Constituents of Geranium Oil

Abstract

Abstract (5 R * ,9 S * )‐ and (5 R * ,9 R * )‐2,2,9‐Trimethyl‐1,6‐dioxaspiro [4.4]non‐3‐ene ( 1a and 1b resp.) and their dihydro derivatives 2a and 2b are described as new constituents of geranium oil. The structures and configurations of 1a , 1b , 2a , and 2b , are based on spectra interpretation and syntheses. Also some other monoterpenoid constituents identified in the same boiling range are discussed.