Über Synthesen in der Aldosteron-Reihe I. Totalsynthese des racemischen Aldosterons

Cd → BCD → Abcd

“…Partial equilibration to the 17/?-epimer could be effected under various conditions including methoxide catalysis. At this point, the work converged with that of Wettstein and his collaborators who had obtained both epimers and converted the 17/?-analog of 88 to aldosterone [77][78][79]. Johnson, however, developed an alternative procedure utilizing the 17a:-epimer.…”

Bc → Abc → Abcd

“…Two years later, the Swiss group at Ciba achieved the total synthesis of this powerful adrenal cortical hormone [61]. By 1958, at least four more syntheses were announced by different groups [62][63][64][65].…”

“…The starting material in the total synthesis of aldosterone [61,[66][67][68] by Schmidlin, Anner, Billeter, and Wettstein was the Sarett's ketone 50 (Scheme 9-9). Condensation of this compound with ethyl carbonate afforded the keto ester 81, w T hich was alkylated with methallyl iodide to give the substituted keto ester 82.…”

“…Oxidation of this product 84 with osmium tetroxide led to a mixture of triols 86, which upon selective hydrogénation, afforded the vinylcarbinols 87. The latter were converted into a mixture of cis-transisomeric aldehyde 88, by successive treatment with periodic acid and phosphorous tribromide [61,67]. In an alternative method [67], the compound 84 was ozonized to give the hydroxy ketone 85.…”

Designing Total Syntheses

“…Attacks were mounted on other steroids, and in 1948 the stereochemically much more complex steroid estrone was conquered [18]. A spate of syntheses then followed, some of which are chronicled in Table 1-1 [17][18][19][20][21][22][23][24][25][26][27][28]. On examination of these structures, one is immediately impressed with their stereochemical complexity, and it becomes understandable that the solution of these formidable synthetic problems would have been infinitely more difficult without the timely introduction of the concepts of conformational analysis [29].…”