Total Synthesis of a Cytotoxic Acetogenin, Pyranicin
摘要:
The first total synthesis of a new cytotoxic acetogenin, pyranicin (1), is described. SmI2-induced reductive cyclization of beta-alkoxy acrylate 4 proceeded stereoselectively to give 16,20-syn,-19,20-trans-THP derivative 14, which was efficiently transformed into the 19,20-cis-THP derivative 18 through Mitsunobu lactonization. Wittig reaction of the phosphonium salt 2 obtained therefrom with butenolide 3 at -78 degreesC followed by reduction and deprotection afforded 1 in good overall yield.
Total Synthesis of a Cytotoxic Acetogenin, Pyranicin
摘要:
The first total synthesis of a new cytotoxic acetogenin, pyranicin (1), is described. SmI2-induced reductive cyclization of beta-alkoxy acrylate 4 proceeded stereoselectively to give 16,20-syn,-19,20-trans-THP derivative 14, which was efficiently transformed into the 19,20-cis-THP derivative 18 through Mitsunobu lactonization. Wittig reaction of the phosphonium salt 2 obtained therefrom with butenolide 3 at -78 degreesC followed by reduction and deprotection afforded 1 in good overall yield.
An Efficient Convergent Access to Spiroketal Segment of (+)-Spiroxaline Methyl Ether
作者:Narshinha Argade、Mandeep Singh
DOI:10.1055/s-0030-1258456
日期:2011.4
Starting from trimethylsilylacetylene, a facilesynthesis of optically pure spiroketal unit of (+)-spiroxaline methyl ether has been described. The synthesis entails stepwise alkylation and acylation of an alkyne with two different readily available chiral building blocks followed by the reductive in situ regio- and stereoselective spiroketalization pathway. alkyne - (R)-oxirane - (R)-γ-valerolactone