135504-98-2Relevant academic research and scientific papers
Synthesis of Shikonin and Alkannin
Braun, Manfred,Bauer, Claus
, p. 1157 - 1164 (2007/10/02)
The enantiomeric naturally occurring naphthoquinones shikonin and alkannin have been synthesized in a thirteen-step procedure in 44 to 65percent e.e.The stereogenic centers of (R)-1 and (S)-1 are created by the reaction of naphthaldehyde 3 with (R)- and (S)-2-hydroxy-1,2,2-triphenylethyl acetate (2), respectively.In order to find out a rationalization for the unexpectedly low diastereoselectivity in this aldol addition, a series of substituted aromatic aldehydes 12a-h has been treated with (R)-2. Key words: Naphthoquinone / Aldol addition / (R)-Shikonin / (S)-Alkannin
