[4'R,5'R-(1S-cis)]-1-ethynyl-4',5'-dimethylspiro[bicyclo[3.1.0]hexene-2,2'-[1,3]dioxolane]

(4'R-(2'α(1S*,5R*),4'α,5β))-4',5'-dimethylspiro(bicyclo(3.1.0)hexane-2,2'-(1,3)dioxolane)-1-carboxaldehyde