The Preparation of Enantiomerically Pure 3,4-Epoxy-1-butene and 3-Butene-1,2-diol

Abstract

Single enantiomer 2-hydroxy-3-butenyl tosylate is a key precursor for single enantiomer 3,4-epoxy-1-butene and 3-butene-1,2-diol. The epoxide results from ring-closure of the hydroxytosylate while the diol is obtained through the intermediacy of the corresponding cyclic carbonate. This latter sequence avoids the loss of enantiomeric purity observed through direct hydrolysis.

Iridium-Catalyzed Enantioselective Ring Opening of Alkenyl Oxiranes by Unactivated Carboxylic Acids

“…These compounds have either limited commercial availability or are available at high cost. From, ( S )- 8 and ( R )- 8 , corresponding vinyl oxiranes ( S )- 23 and ( R )- 23 can be prepared following known conditions without loss of ee …”

“…It is worth mentioning that there is no straightforward synthesis available to afford this kind of 9-membered lactones bearing a stereocenter at the C−O bond. A short and very efficient formal synthesis of goitrin (21) and epigoitrin (22), which are enantiomeric to each other is also possible (Scheme 2E). These two compounds can be prepared following a known path 19 from highly enantiopure vinylic diol (S)-8 or (R)-8.…”

“…These two compounds can be prepared following a known path 19 from highly enantiopure vinylic diol (S)-8 or (R)-8. Goitrin (21) shows antithyroid properties while epigoitrin (22) exhibits strong antiviral activity. Epigoitrin (22) was previously synthesized in nine steps from ascorbic acid 19 and seven steps from (R)-(+)-4-Hydroxy-γ-butyrolactone.…”

“…Epigoitrin (22) was previously synthesized in nine steps from ascorbic acid 19 and seven steps from (R)-(+)-4-Hydroxy-γ-butyrolactone. 20 To set the correct stereocenter for goitrin (21), the key intermediate diol (S)-8 was obtained in high enantiopurity and high yield using (S)-L, while for epigoitrin ( 22), the opposite enantiomer (R)-8 was obtained by utilizing (R)-L. From (S)-8 and (R)-8, (S)-23 and (R)-23 can be afforded very easily following a reported method in high yields. 21 These compounds have either limited commercial availability or are available at high cost.…”

“…20 To set the correct stereocenter for goitrin (21), the key intermediate diol (S)-8 was obtained in high enantiopurity and high yield using (S)-L, while for epigoitrin ( 22), the opposite enantiomer (R)-8 was obtained by utilizing (R)-L. From (S)-8 and (R)-8, (S)-23 and (R)-23 can be afforded very easily following a reported method in high yields. 21 These compounds have either limited commercial availability or are available at high cost. From, (S)-8 and (R)-8, corresponding vinyl oxiranes (S)-23 and (R)-23 can be prepared following known conditions without loss of ee.…”