Synthesis and absolute configuration of (‐)‐meridinol and (‐)‐3‐epimeridinol

Takano, Daisuke; Doe, Matsumi; Morimoto, Yoshiki; Kinoshita, Takamasa; Yoshihara, Kazuo

doi:10.1002/jhet.5570360134

Cited by 6 publications

(1 citation statement)

References 14 publications

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“…An analogous approach from malic acid was recently reported for the enantioselective total synthesis of (−)-meridinol. Disadvantages of this synthesis were a reduction/reoxidation sequence and an almost unselective second alkylation affording the natural product in only 3.3% overall yield over eight steps 7 …”

Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of (−)-Wikstromol Using a New Approach via Malic Acid

Sefkow

2001

J. Org. Chem.

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The total synthesis of (-)-wikstromol, a bioactive alpha-hydroxylated lactone lignan, from natural malic acid using a consecutive alkylation strategy is presented. First, alkylation of a malic acid ester provided the monobenzyl derivative, which was then converted to an alpha-substituted dioxolanone. This derivative was reacted in a second alkylation step to a double benzylated dioxolanone, which was transformed to bis-O-benzyl-protected (-)-wikstromol and subsequently to the natural product. Only six steps were required to produce wikstromol in 30% overall yield. A second approach from malic acid, the double alkylation of dienolates from 5-oxo-1,3-dioxolan-4-yl acetic acid derivatives, was not successful. No reaction conditions were found to afford the dienolates. Instead, rapid fragmentation of the dioxolanones to fumaric acid derivatives and pivalaldehyde occurred even at -105 degrees C, and aldol reaction products with good stereoselectivity were formed. The relative configuration of the major isomer was determined by X-ray structure analysis. By comparison of NMR data it is shown that a previous assignment of the configuration of one of the described aldol products was incorrect.

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Section: Resultsmentioning

confidence: 99%