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Enantiocomplementary Preparation of Optically Pure 2-Trimethylsilylethynyl-2-cyclopentenol by Homochiralization of Racemic Precursors: a New Route to the Key Intermediate of 1,25-Dihydroxycholecalciferol and Vincamine by Seiichi Takano; Mahito Suzuki; Kunio Ogasawara is a Chemistry article available to read on EtoBox.

What is Enantiocomplementary Preparation of Optically Pure 2-Trimethylsilylethynyl-2-cyclopentenol by Homochiralization of Racemic Precursors: a New Route to the Key Intermediate of 1,25-Dihydroxycholecalciferol and Vincamine about?

Treatment of racemic 2-trimethylsilylethynyl-2cyclopentenol [(+l] with vinyl acetate in the presence of lipase PS in toluene yielded a 1:l mixture of the unreacted (S)alcohol [(Q-l] and the (R)-acetate [(R)-71 which without isolation afforded the chirally homogeneous (R)-alcohol [(R)-1] in 73% overall yield on reaction with acetic acid in the same reaction medium in the presence of diisopropyl azodicarboxylate and triphenylphosphine, followed by reductive deacylation of the resulting (R)-acetate [(R)-71. On the other hand, hydrolysis of the racemic acetate [(&)-71, obtained from [4)-l], in a phosphate buffer solution in the presence of lipase PS yielded a 1: 1 mixture of the (R)-alcohol [(R)-1] and the unreacted @)-acetate [(S)-71 which without separation, furnished the enantiomerically homogeneous (S)alcohol r(S)-1] in 75% overall yield on treatment with acetic acid under the above Mitsunobu conditions, followed by reductive deacylation of the resulting @)-acetate [(S)-7].

Who reads Enantiocomplementary Preparation of Optically Pure 2-Trimethylsilylethynyl-2-cyclopentenol by Homochiralization of Racemic Precursors: a New Route to the Key Intermediate of 1,25-Dihydroxycholecalciferol and Vincamine?

Author

Seiichi Takano; Mahito Suzuki; Kunio Ogasawara

Publisher

Elsevier Science; Elsevier ; Elsevier Ltd.; Elsevier BV (ISSN 0957-4166)

Published

1993

Language

EN

Field

Chemistry (Physical Sciences)