Piers, Edward published the artcileStereoselective total synthesis of copa and ylango sesquiterpenoids. Preparation of (-)-(1S,4S,5R,7R)-1,7-dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione and (+)-(1R,4S,5S,7S)-1,7-dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione, Synthetic Route of 31253-08-4, the publication is Canadian Journal of Chemistry (1975), 53(19), 2827-37, database is CAplus.
The efficient, stereoselective syntheses of 2 diastereomeric bicyclo[3.2.1]octadiones (I, II) are described and the potential use of these materials for the synthesis of the copa (III, R,R1 = O; R = H,R1 = OH, R = OH, R1 = H; IV, V and the ylango (VI,RR1 = O;R = H,R1 = OH;R = OH,R1 = H; VII,VIII) sesquiterpenoids, resp., is outlined. Conversion of (+)-carvomenthone (IX,Z = H2) into the corresponding n-butylthiomethylene derivative [IX,Z = CHS(CH2)3Me], followed by alkylation of the latter with EtO2CCHIMe, gave dione [X,R = Et,Z = CHS(CH2)3Me]. Removal of the blocking group from the latter was accompanied by ester hydrolysis and afforded keto acid (X,R = H,Z = H2). An efficient intramolecular Claisen condensation of the corresponding ester (X,R = Me,Z = H2) yielded (-)-(1S,4S,5R,7R)-1,7-dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione (I). Conversion of the known octalone XI (R = H,Z = H2) into the cross-conjugated keto aldehyde XII was accomplished by standard reactions. Treatment of the latter with LiCuMe2, followed by trapping of the resultant enolate anion with AcCl gave XI(R = Me,Z = CHOAc). Oxidative ozonolysis of this material yielded the keto acid XIII (R = H). Esterification of the latter, followed by intramol. Claisen condensation of the resulting keto ester XIII,R = Me, afforded (+)-(1R,4S,5S,7S)-1,7-dimethyl-4-isopropylbicyclo[3.2.1]octa-6,8-dione (II).
Canadian Journal of Chemistry published new progress about 31253-08-4. 31253-08-4 belongs to iodides-buliding-blocks, auxiliary class Iodide,Ester, name is Ethyl 2-Iodopropionate, and the molecular formula is C5H9IO2, Synthetic Route of 31253-08-4.
Referemce:
https://en.wikipedia.org/wiki/Iodide,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com