115793-31-2Relevant academic research and scientific papers
Chiral γ-(tetrahydropyranyloxy)allylstannane: a new chiral reagent for the asymmetric synthesis of syn 1,2-diols
Kadota, Isao,Kobayashi, Katsumi,Okano, Hiroshi,Asao, Naoki,Yamamoto, Yoshinori
, p. 615 - 623 (2007/10/02)
(2R,3S)-3-Allyloxy-3,4,5,6-tetrahydro-2H-pyran-2-methanol was prepared in high yield from tri-O-acetyl-D-glucal, an easily available and cheap chiral source.The hydroxy group was protected as the t-butyldiphenylsilyl ether, and the allyl group was converted to the corresponding allyl stannane via formation of allyl carbanion and subsequent trapping with tributylstannyl chloride.The γ-alkoxy allyl stannane 1 bearing the (2R,3S)-2--3,4,5,6-tetrahydro-2H-pyran-3-yloxy auxiliary at the allyl terminus was prepared by this procedure.The reaction of 1 with aldehydes in the presence of AlCl3*OEt2 or AlCl3 gave the corresponding syn adducts 2 with high diastereoselectivities; the ratio of syn/anti > 97:3.The diastereomeric excess of the syn adducts 2, that is, the ratio 2/(2 + the (S,S) isomer of 2), varied from 85 to 94percent.Removal of the protecting group of 2 gave the (R,R) diols 3.The high diastereo- and enantioselectivity in the formation of the (R,R) isomer is accounted for by an anti S'E transition state 18. allylstannane / γ-alkoxyallylstannane / asymmetric synthesis / syn-1,2-diol / Lewis acid / allylstannane-aldehyde condensation / γ-(tetrahydropyranyloxy)allylstannane / anti S'E
Asymmetric Synthesis of Syn 1,2-Diols via the Reaction of Aldehydes with Chiral γ-(Tetrahydropyranyloxy)allylstannanes
Yamamoto, Yoshinori,Kobayashi, Katsumi,Okano, Hiroshi,Kadota, Isao
, p. 7003 - 7005 (2007/10/02)
Asymmetric synthesis of syn 1,2-diols 3 has been accomplished via the reaction of the chiral γ-alkoxy-substituted allylstannane 1 with aldehydes in the presence of AlCl3 or AlCl3*OEt2, followed by a five-step operation to remove the chiral auxiliary.
Cyclic ether derivatives and their use
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, (2008/06/13)
Compounds of formula (I): STR1 (wherein: l is 2-4; A and B are oxygen or sulfur; one of R1 and R2 represents a long chain alkyl, alkylcarbamoyl or aliphatic acyl group and the other of R1 and R2 represents a group of formula (III) or (IIf): STR2 in which E represents a single bond, a bivalent heterocyclic group or a group of formula --CO--, --COO-- or --CONR6 --, where R6 is hydrogen or an imino-protecting group; m is 0-3; n is 0-10; q is 0 or 1; R4 is optionally protected hydroxy, mercapto group or carboxy; Q is an amino or nitrogen-containing heterocyclic group; Rf4 Rf5 and Rf6 are independently selected from the group consisting of hydrogen atoms and C1 -C6 alkyl groups, or Rf4 and Rf5 or Rf4, Rf5 and Rf6, together with the nitrogen atom to which they are attached, form a heterocyclic ring) are PAF antagonists which may be used to treat asthma, hypotension, inflammation and shock. They may be prepared by reacting the corresponding compound having a haloalkyl phosphate ester or alkylenephosphate ester group in place of the ammonioalkyl phosphate ester group with an appropriate amine.
New cyclic ether derivatives, their preparation and their use
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, (2008/06/13)
Compounds of formula (I): [wherein: lis 2 - 4; A and B are oxygen or sulphur; one of R1 and R2 represents a long chain alkyl, alkylcarbamoyl or aliphatic acyl group and the other of R1 and R2 represents a group of formula (III): in which E represents a si
