128261-30-3Relevant academic research and scientific papers
Synthesis of (+/-)-Thaps-7(15)-ene and (+/-)-Thaps-6-enes
Srikrishna, Adusumilli,Krishnan, Kathiresan
, p. 667 - 674 (2007/10/02)
The synthesis of (+/-)-3a,4,4,7a-tetramethylhydrindan-2-one 8, containing three contiguous quaternary carbons as present in thapsanes, and the total synthesis of thaps-7(15)-ene 6 and thaps-6-ene 7, probable biogenetic precursors of thapsanes, have been achieved.Thus, orthoester Claisen rearrangement of cyclogeraniol 14, followed by hydrolysis of the resultant ester 16 furnished the eneacid 13.Copper sulfate-catalysed intramolecular cyclopropanation of the diazo ketone 18, derived from the acid 13, generated the cyclopropyl ketone 12.Regiospecific reductive cleavage of cyclopropyl ketone 12 furnished the hydrindanone 8, whereas the diazo ketone 26 furnished the hydrindanone 28a via the cyclopropyl ketone 27.Wittig methylenation of the hydrindanone 28a furnished thaps-7(15)-ene 6, which on isomerisation gave thaps-6-ene 7.Allylic oxidation of thaps-6-ene furnished the thapsenone 31, a degradation product of the natural thapsane 1b.
STEREOSPECIFIC SYNTHESIS OF THAPS-7(15)-ENE AND THAPS-6-ENE, PROBABLE BIOGENETIC PRECURSORS OF THAPSANES
Srikrishna, A.,Krishnan, K.
, p. 6577 - 6580 (2007/10/02)
Stereospecific synthesis of the title compounds, containing the basic carbocyclic skeleton of thapsanes, based on intramolecular diazoketone cyclopropanation reaction, is described.
