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Partialsynthese der Grandidone A, 7‐Epi‐A, B, 7‐Epi‐B, C, D und 7‐Epi‐D aus 14‐Hydroxytaxodion
Author(s) -
Rüedi Peter,
Uchida Masaaki,
Eugster Conrad Hans
Publication year - 1981
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19810640730
Subject(s) - chemistry , reagent , yield (engineering) , stereochemistry , organic chemistry , metallurgy , materials science
Partial Synthesis of Grandidones A, 7‐Epi‐A, B, 7‐Epi‐B, C, D and 7‐Epi‐D, from 14‐Hydroxytaxodione Oxydative addition of coleon U ( 6 ) to 14‐hydroxytaxodione ( 5 ) in the presence of Fétizon 's reagent mainly leads to grandidone A ( 1a ) and 7‐epigrandidone A ( 1b ) ( ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7‐epigrandidone B ( 2b ) ( ca. 3:1). Dimerization of 14‐hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7‐epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7‐epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14‐hydroxytaxodione ( 5 ) in the presence of Fétizon 's reagent mainly leads to grandidone A ( 1a ) and 7‐epigrandidone A ( 1b ) ( ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7‐epigrandidone B ( 2b ) ( ca. 3:1). Dimerization of 14‐hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7‐epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7‐epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14‐hydroxytaxodione ( 5 ) in the presence of Fétizon 's reagent mainly leads to grandidone A ( 1a ) and 7‐epigrandidone A ( 1b ) ( ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7‐epigrandidone B ( 2b ) ( ca. 3:1). Dimerization of 14‐hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7‐epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7‐epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved. Oxydative addition of coleon U ( 6 ) to 14‐hydroxytaxodione ( 5 ) in the presence of Fétizon 's reagent mainly leads to grandidone A ( 1a ) and 7‐epigrandidone A ( 1b ) ( ca. 15:1), whereas coleon V ( 7 ) and 5 under the same conditions yield grandidone B ( 2a ) and 7‐epigrandidone B ( 2b ) ( ca. 3:1). Dimerization of 14‐hydroxytaxodione ( 5 ) gives grandidone C ( 3 ; ca. 40%), grandidone D ( 4a ; ca. 50%) and 7‐epigrandidone D ( 4b ; ca. 10%). All these compounds obtained by partial synthesis are in every respect identical with the natural products, thus establishing their absolute configurations. The thermal transformation of grandidone C ( 3 ) to grandidone D ( 4a )/7‐epigrandidone D ( 4b ) and interconversions of 4a and 4b were achieved.