86783-96-2Relevant academic research and scientific papers
General access to the Vinca and Tacaman alkaloids using a Rh(II)-catalyzed cyclization/cycloaddition cascade
England, Dylan B.,Padwa, Albert
, p. 2795 - 2802 (2008)
(Chemical Equation Presented) The total synthesis of several members of the vinca and tacaman classes of indole alkaloids has been accomplished. The central step in the synthesis consists of an intramolecular [3+2]-cycloaddition reaction of an α-diazo indoloamide which delivers the pentacyclic skeleton of the natural product in excellent yield. The acid lability of the oxabicyclic structure was exploited to establish the trans-D/E ring fusion of (±)-3H-epivincamine (3). Finally, a base induced keto-amide ring contraction was utilized to generate the E-ring of the natural product. A variation of the cascade sequence of reactions used to synthesize (±)-3H-epivincamine was also employed for the synthesis of the tacaman alkaloids (±)-tacamonine and (±)-apotacamine.
Synthesis of (±)-3H-epivincamine via a Rh(II)-triggered cyclization/cycloaddition cascade
England, Dylan B.,Padwa, Albert
, p. 3249 - 3252 (2008/02/12)
A synthesis of (±)-3H-epivincamine is reported. Important steps include (1) a Rh(II)-catalyzed intramolecular [3+2]-cycloaddition of an α-diazo indolo amide, (2) a reductive ring opening of the cycloadduct, (3) a decarboethoxylation reaction, and (4) a base-induced keto-amide ring contraction.
