Selective transformation of 2,3-epoxy alcohols and related derivatives. Strategies for nucleophilic attack at carbon-1

Abstract

In connection with the continuing recent interest in the stereoselective synthesis of epoxy alcohols, a systematic investigation of the bimolecular nucleophilic ring-opening reactions of acyclic 2,3-epoxy alcohols was undertaken. Strategies for nucleophilic attack at C-l of a 2,3-epoxy alcohol, each of which depends upon the regioselective ring-opening of a 1,2-epoxy 3-ol, were explored. Under Payne rearrangement conditions, i-BuSNa was found to react with 2,3-epoxy alcohols to afford 1-tert-butylthio 2,3-diols. These diols can be readily converted to 1,2-epoxy 3-ols via S-alkylation followed by treatment with base. Alternatively, 1,2-epoxy 3-ols can be prepared from 2,3-epoxy alcohols by sulfonylation and acidic hydrolysis followed by ring-closure of the diol sulfonate intermediate. Dialkylamines were also found to react selectively with 2,3-epoxy alcohols under Payne rearrangement conditions to afford 1-amino 2,3-diols.

C-Galactosylceramide diastereomers via Sharpless asymmetric epoxidation chemistry

“…Sharpless asymmetric epoxidation (SAE)11 using substoichiometric amount of catalysts (50 mol% TTIP, 60 mol% D-(-)-DIPT) ensured conversion of 12 to (2 R , 3 R ) epoxy alcohol 13 in high enantiomeric excess ( ee >95%). Opening the ( 2R, 3R ) epoxy alcohol 13 using NaN 3 /NH 4 Cl in a simple S N 2 conversion provided an inseparable mixture of desired 3-azido-1,2 vicinal diol 14 and by-product 1,3 diol 15 in 90% yield 12. The 8/1 ratio of 14 / 15 was determined at a later stage.…”

Synthesis of (R)-(+)-Tanikolide through Stereospecific C-H Insertion Reaction of Dichlorocarbene with Optically Active Secondary Alcohol Derivatives

“…Homogeneity concerning the stereochemistry and structure of the epoxide (16) prepared via the epoxyaldehyde (17) were determined by chiral HPLC analysis and identification with the compound (16) which was obtained from the chloromethylcarbinol (12). The transformation of the glycol (6) to the epoxy-aldehyde (17) is interpreted to proceed with tandem epoxide migration closely related to the Payne rearrangement [50][51][52] illustrated in Chart 5.…”

Enantiospecific Synthesis of Penehyclidine Hydrochloride and Its Piperidine Derivatives with R Configuration

“…Compound 5 reacted with p-TsCl in CH 2 Cl 2 under ice-bath condition to form the crude mono-sulfornated product that on recrystallization from petroleum ether afforded the pure 4 in 79% yield. 15 However, it was found that the intramolecular Williamson ether synthetic method from 4 to obtain the optical pure epoxide 2 was unsuccessful with NaH and catalytic amount of DMSO in THF, 16 of which the ee value of the 2 only reached 20%-30%. Failed to obtain the chiral epoxide according to this method, it was tried to synthesize the 8018 optical isomers through the following methods.…”