Scalable Synthesis of Enantiomerically Pure syn-2,3-Dihydroxybutyrate by Sharpless Asymmetric Dihydroxylation of p-Phenylbenzyl Crotonate
摘要:
An efficient four-step synthetic route to the useful chiral building block (2R,3S)-dihydroxybutyric acid acetonide in >95% ee is detailed. The sequence is readily scaled, requires no chromatography, and allows for efficient recycling of p-phenylbenzyl alcohol, an expedient for enantio- and diastereoenrichment by recrystallization.
Hydrogen bonds can play a prominent role in organometallic catalysis, as shown for the title reaction, in which a counteranion directs the cyclization through the formation of hydrogen bonds that likely involve a proton of the π‐allyl/palladium species itself. The reaction allows access to four out of the eight stereoisomers of 2,5‐disubstitued 3‐hydroxy‐tetrahydrofurans and thus fragments of complex