General approach to halogenated tetrahydrofuran natural products from red algae of the genus Laurencia. Total synthesis of (.+-.)-trans-kumausyne and demonstration of an …

Abstract:

A general strategy for the synthesis of C15 halogenated tetrahydrofuranoid lipids from red algae of the genus Laurencia has been developed. The central step is the convenient formation of hydrobenzofuranone (±)-5 on a large scale, and with complete stereocontrol, from the acid-catalyzed condensation of l-vinylcyclopentanediol (3) and a-(benzyloxy) acetaldehyde (Scheme II). Starting with the chiral, nonracemic (15, 2/?)-diol 3, hydrobenzofuranone (-)-S is also available in good enantiomeric purity (Scheme V). The total synthesis of (±)-r/ww-kumausyne from roc-5 is accomplished in 13 steps and> 5% overall yield. A rich variety of halogenated, nonisoprenoid sesquiterpenes have been isolated from the widely distributed red algae of the genus Laurencia, 1 The majority of these metabolites can be envisaged to arise from the halocyclization of various 6, 7-dihydroxy-pentadeca-3, 9, 12-trien-l-ynes (laubkp_rediols). 2 A …

Año de publicación:

1991

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