
TY  - JOUR
A1  - Collins, DJ 
A1  - Jhingran, AG 
A1  - Rutschmann, SB 
T1  - Enolic Ortho Esters. IV. Synthesis of the 8-&#945; and 8-&#946; Epimers of a 6-Oxa Steroidal Enolic Ortho Ester
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1989
VL  - 42
IS  - 10
SP  - 1769
EP  - 1784
KW  - 
UR  - https://doi.org/10.1071/CH9891769 
N2  - Reaction of resorcinol (9) with methyl 1&#946;-hydroxy-7a&#946;-methyl-5-oxo-2,3,3 a  &#945;,4,5,6,7,7a- octahydro-1H-indene-4&#945;-carboxylate (10a) or with the corresponding 1,5-dioxo ester (15) in methanesulfonic acid gave ( ±)-3,17  &#946;-dihydroxy-6-oxaestra-l,3,5(10),8(9)-tetraen-7-one (11a) (98%), or (c)-3-hydroxy-6-oxaestra-1,3,5(10),8(9)-tetraene-7,17-dione (14) (91%), respectively. 3-O-Methylation of the phenolic keto lactone (14) followed by reaction with ethylene glycol gave (±)-17,17-ethylenedioxy-3-methoxy-6-oxaestra-1,3,5(10),8(9)- tetrae n-7-one (16). Reduction of this with lithium/ammonia afforded 77% of (±) 17,17-ethylenedioxy-3-methoxy-6-oxa-8 &#945;-estra-1,3,5(10)-trien-7-one (71, which upon base-catalysed epimerization yielded 84% of the 8 &#946;-epimer (19). Reaction of the 8 &#945;-H lactone (17) or its 8 &#946;- epimer (19) with ethylene oxide in the presence of boron trifluoride etherate yielded the corresponding phenolic ortho esters (±)-7,7:17,17-bis( ethylenedioxy )-3-methoxy-6-oxa-8 &#945;-estra-1,3,S(10)- triene (23), and its 8 &#946;- epimer (25), in 36 and 42% yields, respectively. Birch reduction of (23) and (25) afforded the corresponding enolic ortho ester ( ±)-7,7:17,17-bis( ethylenedioxy )-3-methoxy-6-oxa-8 &#945;-estra-2,5(10)- diene (26), and its 8 &#946;-epimer (6), in 82 and 64% yields, respectively. Some related chemistry is described. The enolic ortho esters (26) and (6) were relatively inert to attack by methylmagne sium iodide under normal conditions. 
ER  -

