85148-25-0Relevant academic research and scientific papers
Preparation of Enantiopure Precursors for the Vitamin E Synthesis. A Comparison of the Asymmetric Allylation of Ketones and the Sharpless Bishydroxylation
Tietze, Lutz F.,G?rlitzer, Jochen
, p. 1049 - 1050 (2007/10/03)
The enantioselective synthesis of the precursors 9, 10, 16 and 17 for the preparation of enantiopure vitamin E by asymmetric allylation of the ketone 6 and Sharpless bishydroxylation of the aliphatic alkenes 11 and 15 is described.
A Synthesis of Natural α-Tocopherol Intermediate
Sugai, Takeshi,Watanabe, Naoyuki,Ohta, Hiromichi
, p. 371 - 376 (2007/10/02)
(S)-(-)-6-Hydroxy-2,5,7,8-tetramethyl-2-chromanmethanol, an intermediate of natural α-tocopherol was synthesized from (S)-2-benzyloxy-2-methyl-4-pentenoic acid, which was obtained by the enzymatic hydrolysis of the corresponding racemic methyl ester.
Total synthesis of naturally occurring α-tocopherol. Assymetric alkylation and asymmetric epoxidation as means to introduce (R)-configuration at C(2) of the chroman moiety
Hubscher,Barner
, p. 1068 - 1086 (2007/10/02)
Based on the reductive, stereospecific ring closure of (2R,4'R,8'R)-α-'Tocopherylquinone' or corresponding analogues with a short, functionalized side chain (B, Scheme 1) to 1 resp. the chroman system of 1 (C), two different approaches for the introduction of the required tertiary methyl-substituted alcohol structure in the side chain of the aromatic precursors (A, Scheme 1) were developed. The first approach uses asymmetric alkylation in three different versions featuring a) diastereoselective steering with chiral auxiliaries I-IV (Scheme 2) attached as esters to α-keto acids, b) intermediate transfer of chirality in an ester enolate (from 18, Scheme 4) derived from an optically active α-hydroxyacid, c) enantioselective alkylation of phytenal (20) and subsequent ring closure with chirality transfer (Schemes 5-7). The second approach is based on the asymmetric epoxidation of β-metallylalcohol (Sharpless epoxidation), the corresponding epoxyalcohol being converted in situ to the (S)- or (R)-chlorodiol (S)- and (R)-29, respectively, for isolation (Schemes 8 and 9). Nucleophilic epoxide opening with a (3R,7R)-3,7,11-trimethyldodecyl (C15**) and an ArCH2 unit in appropriate sequence is used to assemble the C-framework of the target molecule via corresponding epoxide intermediates from either chlorodiol. Combined with the use of the methoxymethyl-ether function for protection of the hydroquinone system, the epoxide approach provides a short route to 1 (Scheme 10).
Process for the preparation of hydroquinone derivatives and d-α-tocopherol
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, (2008/06/13)
In this process of the invention a compound of the formula STR1 wherein R is a leaving group, is reacted with a compound of the formula STR2 wherein R1 is an ether protecting group, and, if desired a thus-obtained compound of the formula STR3 i
Hydroquinone derivatives and a process for their preparation
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, (2008/06/13)
Compound of the general formula STR1 wherein R represents an ether protecting group useful as intermediates.
Hydroquinone derivatives useful in the production of vitamin E
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, (2008/06/13)
The present invention is directed to novel hydroquinone derivatives which are useful as intermediates for the manufacture of (R,R,R)-α-tocopherol (natural vitamin E) as well as of racemic α-tocopherol. The invention is also directed to a process for the preparation of the hydroquinone derivatives of the invention.
Process for the manufacture of optically active compounds
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, (2008/06/13)
There is described a novel process for producing hydroquinone derivatives of the formula STR1 wherein R is an ether protecting group, and their conversion into d-α-tocopherol, starting from compounds of the formula STR2 wherein R is an ether protecting group and R1 is hydrogen or an ether protecting group.
AN EFFICIENT SYNTHESIS OF (S)-CHROMANMETHANOL, A VITAMIN E PRECURSOR
Takabe, Kunihiko,Okisaka, Koichi,Uchiyama, Yujiro,Katagiri, Takao,Yoda, Hidemi
, p. 561 - 562 (2007/10/02)
The (S)-chromanmethanol, a key intermediate for the synthesis of optically active α-tocopherol was synthesized by a reaction sequence which utilized the asymmetric epoxidation of the (E)-allylic alcohol to the (2R,3R)-epoxyalcohol in high enantiomeric exc
Synthesis of 6-hydroxychroman-2-methanol derivatives
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, (2008/06/13)
A process for producing chroman, a compound of the formula, STR1 or an optically active compound thereof wherein R2, R3 and R4 are each a hydrogen atom or a C1 -C4 alkyl group, which comprises reactin
ASYMMETRIC SYNTHESIS OF A CHROMAN DERIVATIVE (VITAMIN E PRECURSOR)
Sakito, Yoji,Suzukamo, Gohfu
, p. 4953 - 4954 (2007/10/02)
Chromanmethanol 2, a chiral intermediate for the synthesis of α-tocopherol 1, is prepared from α-hydroxy aldehyde 5, which is obtained by an asymmetric synthesis in over 95percent ee.
