Catalytic Wittig and Mitsunobu reactions
AssigneeBoard of Regents, The University of Texas System
InventorChristopher J. O'Brien
Life of this patent
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Abstract
A catalytic Wittig method utilizing a phosphine including the steps of providing a phosphine oxide precatalyst and reducing the phosphine oxide precatalyst to produce the phosphine; forming a phosphonium ylide precursor from the phosphine and a reactant; generating a phosphonium ylide from the phosphonium ylide precursor; reacting the phosphonium ylide precursor with the aldehyde, ketone, or ester to form the olefin and the phosphine oxide which then reenters the cycle. The invention is also directed to a Mitsunobu reaction catalytic in phosphine.
Claims23
A one-pot catalytic Wittig method to form an olefin from an organohalide and an aldehyde or ketone comprising the steps:
- a) providing i) the organohalide, ii) the aldehyde or ketone, iii) a phosphine oxide, and iv) a silane reducing agent;
- b) reducing the phosphine oxide with the silane reducing agent to produce a phosphine;
- c) forming a phosphonium ylide precursor with the phosphine and organohalide;
- d) generating a phosphonium ylide from the phosphonium ylide precursor;
- and
- e) reacting the phosphonium ylide with the aldehyde or ketone to form the olefin and said phosphine oxide;
- wherein the phosphine oxide is selected from the group:
- wherein n is between 0 and 4;
- m is between 0 and 14;
- and R is an alkyl;
- R1, R2, and R3 are each an alkyl, aryl, alkoxy, or heteroaryl;
- and the organohalide is a primary or secondary organohalide.
A method for the chemoselective reduction of a phosphine oxide to a phosphine in the presence of an organohalide, an aldehyde or a ketone, and an alkene;
- wherein said phosphine oxide is reduced using a silane reducing agent.
Dependencies are inferred from the claim text.