Enantioselective total synthesis of hydramicromelin B

The first total synthesis of hydramicromelin B is described. An AuCl3/AgOTf-catalyzed intramolecular reaction was used as key step for the construction the coumarin ring.

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(S)-1-(4-(Benzyloxy)-2-methoxyphenyl)ethane-1,2-diolC22H32O4Ee >98% [by chiral HPLC][α]D25=+21.6 (c 4.0, CHCl3)Source of chirality: AD-mix-α

(2R,3S,4S)-Ethyl 4-(4-(benzyloxy)-2-methoxyphenyl)-2,3-dihydroxy-4-(methoxymethoxy)-2-methylbutanoateC23H30O9De = 86%[α]D25=+20.0 (c 2.0, CHCl3)Source of chirality: AD-mix-α

4-((2R,3R,4S)-Tetrahydro-3,4-dihydroxy-4-methyl-5-oxofuran-2-yl)-3-methoxyphenyl propiolateC26H34O8[α]D25=+17.0 (c 1.0, CHCl3)Source of chirality: AD-mix-α