(R)-7,10-diethoxy-8-isopropyl-6,9-diazaspiro[4.5]deca-2,6,9-triene

(2R,5S)-5-allyl-3,6-diethoxy-2,5-dihydro-2-isopropylpyrazine

(2R)-5,5-diallyl-3,6-diethoxy-2,5-dihydro-2-isopropylpyrazine

3-环戊烯-1,1-二甲酸二乙酯

乙基1-(氯甲酰基)-3-环戊烯-1-羧酸酯