Alkene syn dihydroxylation with malonoyl peroxides.

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Alkene dihydroxylation is a fundamental transformation in organic synthesis.
• Developing efficient and selective methods for dihydroxylation remains an active area of research.

Purpose of the Study:

• To introduce cyclopropyl malonoyl peroxide (1) as a novel reagent for alkene dihydroxylation.
• To investigate the stereoselectivity of the dihydroxylation reaction, particularly with 1,2-disubstituted alkenes.

Main Methods:

• Preparation of cyclopropyl malonoyl peroxide (1) from a commercially available diacid.
• Reaction of alkene with reagent 1 in the presence of water at 40 °C.
• Alkaline hydrolysis of the intermediate to yield the final diol product.

Main Results:

• Cyclopropyl malonoyl peroxide (1) effectively dihydroxylates alkenes, affording diols in 40-93% yield.
• The reaction exhibits high syn selectivity for 1,2-disubstituted alkenes, with selectivity ratios ranging from 3:1 to over 50:1.
• Oxygen-labeling studies support the proposed reaction mechanism.

Conclusions:

• Cyclopropyl malonoyl peroxide (1) is a valuable and efficient reagent for alkene dihydroxylation.
• The method provides a stereoselective route to syn-diols, expanding synthetic possibilities.
• The proposed mechanism offers insight into the reaction pathway.