ChemInform Abstract: Chemistry of Glucal Halohydrins: Effect of the Halide on Epoxide Formation.

Lithium triethylborohydride was shown to react with methyl 4,6-O-benzylidene-α-D-hexopyranoside 2- and 3-tosylates, and 2,3-ditosylates, in the manno, allo, and altro configurational series both by O—S fission (O-desulfonylation) and by C—O fission (C-desulfonyloxylation), to produce carbinol and deoxy functions, respectively. The results were compared with those previously obtained with the corresponding gluco and galacto isomers, and the degree of facility of the cleavage reactions was seen to depend on the position of the sulfonic ester groups and the overall configuration of the molecules. The mechanism of reductive desulfonyloxylation also depended on configuration and was demonstrated to involve intermediary epoxide formation or displacement by internal hydride shift as the principal paths; competing elimination and direct nucleophilic displacement were found to occur in the allo series, whereas reduction accompanied by ring contraction has thus far been encountered only in the conformationally less constrained, cis-fused acetal system of the galacto series. Like the borohydride reagent, lithium aluminum hydride was found to react (though much more slowly) with the altro 2,3-ditosylate by the epoxide-mediated mechanism, although the latter hydride is known to desulfonyloxylate the α-D-gluco-isomer by a different, intramolecular reduction mechanism.

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Epoxide formation from (2S,3S)-threitol 1,4-bismethanesulfonate. Preparation and biological activity of (2S,3S)-1,2-epoxy-3,4-butanediol 4-methanesulfonate

Journal of Medicinal Chemistry ◽

10.1021/jm00300a034 ◽

1970 ◽

Vol 13 (6) ◽

pp. 1173-1175 ◽

Cited By ~ 49

Author(s):

Peter W. Feit ◽

Niels Rastrup-Andersen ◽

Rene Matagne

Keyword(s):

Biological Activity ◽

Epoxide Formation

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Epoxide formation in the enzymic conversion of [4-2H]exomethylene cephalosporin C by deacetoxy-/deacetylcephalosporin C synthase

Journal of the Chemical Society Chemical Communications ◽

10.1039/c39920001448 ◽

1992 ◽

pp. 1448 ◽

Cited By ~ 8

Author(s):

Jack E. Baldwin ◽

Robert M. Adlington ◽

Nicholas P. Crouch ◽

In�s A. C. Pereira

Keyword(s):

Cephalosporin C ◽

Epoxide Formation

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Multistep Reaction Processes in Epoxide Formation from 1-Chloro-2-methyl-2-propanol on Ag(110) Revealed by TPXPS and TPD Experiments

The Journal of Physical Chemistry B ◽

10.1021/jp035892e ◽

2003 ◽

Vol 107 (50) ◽

pp. 13976-13985 ◽

Cited By ~ 15

Author(s):

H. Piao ◽

K. Adib ◽

Z. Chang ◽

J. Hrbek ◽

M. Enever ◽

...

Keyword(s):

Reaction Processes ◽

Multistep Reaction ◽

Epoxide Formation

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Aziridinyl imines in organic synthesis: Development of tandem reaction strategies and application to total synthesis of natural products

Pure and Applied Chemistry ◽

10.1351/pac-con-12-10-01 ◽

2013 ◽

Vol 85 (4) ◽

pp. 741-753 ◽

Cited By ~ 11

Author(s):

Hee-Yoon Lee ◽

Seog-Beom Song ◽

Taek Kang ◽

Yoon Jung Kim ◽

Su Jeong Geum

Keyword(s):

Natural Products ◽

Total Synthesis ◽

Organic Synthesis ◽

Reactive Intermediates ◽

Diazo Compounds ◽

Tandem Reaction ◽

Cycloaddition Reactions ◽

Free Radical Reactions ◽

Sulfur Ylide ◽

Epoxide Formation

Aziridinyl imines are well-known carbene equivalents because they are precursors of diazo compounds from which reactive intermediates can be produced. These carbene equivalents can be utilized as zwitterionic species, diradicals, or 4π system for cycloaddition reactions. Thus, the intermediates derived from aziridinyl imines have been used in the sulfur-ylide-mediated epoxide formation, tandem free-radical reactions, or cyclopropanation reaction via carbene intermediates to form trimethylenemethane (TMM) diyls, which undergo [2 + 3] cycloaddition reactions to form cyclopentanoids. Diazo compounds generated from aziridinyl imines also react with allenes to form TMM diyls. This reaction was utilized in tandem cycloaddition reactions of linear substrates to form polyquinanes. These tandem reaction strategies were successfully applied to the total synthesis of various cyclopentanoid natural products.

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