Stereoselective total synthesis of (±)-Samin, the general furofuran lignan precursor
摘要:
A concise stereoselective synthesis of the general furofuran lignan precursor (+/-)-Samin 1 has been achieved through a radical annulation reaction in good overall yield.
Stereoselective Synthesis of Polysubstituted Tetrahydrofurans by Radical Cyclization of Epoxides Using a Transition-Metal Radical Source. Application to the Total Synthesis of (±)-Methylenolactocin and (±)-Protolichesterinic Acid
摘要:
Radical cyclization reactions of substituted alpha-(prop-2-ynyloxy) epoxides using bis(cyclopentadienyl)-titanium(III) chloride as the radical source resulted in polysubstituted tetrahydrofurans. Titanium(III) species were prepared in situ from commercially available titanocene dichloride and zinc dust in tetrahydrofuran, Upon radical cyclization, 2-aryl epoxides 3a-e afforded only trans products 4a-e whereas the 2-alkyl epoxides 3f-h formed a mixture of isomeric products 4f-h in a ratio of 5:1. Some of the aryl tetrahydrofuran derivatives have already been used for the synthesis of bioactive furofuran lignans. 2-Pentyl-3-(hydroxymethyl)-4-methylenetetrahydrofuran (4f) and 2-tridecyl-3-(hydroxymethyl)-4-methylenetetrahydrofuran (4g) have been transformed to two antitumor antibiotics (+/-)-methylenolactocin (1f) and (+/-)-protolichesterinic acid (1g), respectively, in good overall yield.
Stereoselective total synthesis of (±)-Paulownin and (±)-Isogmelinol through radical annulation route
作者:Subhas Chandra Roy、Sankar Adhikari
DOI:10.1016/s0040-4020(01)81924-4
日期:1993.1
A highly stereocontrolledsynthesis of furofuran lignans, (±)-Paulownin (1a) and (±)-Isogmelinol (1b) is described involving intramolecular radical cyclisation as a key step.
Stereoselective radical annulation route to the synthesis of (±)-paulownin and (±)-isogmelinol
作者:Sankar Adhikari、Subhas Roy
DOI:10.1016/s0040-4039(00)61118-8
日期:1992.9
A highly stereocontrolled synthesis of (+/-)-paulownin (1a) and (+/-)-isogmelinol (1b) is reported involving intramolecular radical cyclisation reaction as a key step.
Stereoselective total synthesis of (±)-samin and the dimethoxy analogue, the general furofuran lignan precursors
作者:Gourhari Maiti、Sankar Adhikari、Subhas Chandra Roy
DOI:10.1016/0040-4020(95)00450-m
日期:1995.7
A concise stereoselective synthesis of the general furofuran lignan precursors (+/-)-Samin 1a and its dimethoxy analogue 1b has been achieved through a radical annulation reaction in good overall yield.