Aqueous Ti(IV)-Catalyzed Diels-Alder Reaction

Kyle E Litz

doi:10.3390/12081674

Abstract

The aqueous Diels-Alder reaction of 1,3-cyclohexadiene with 1,4-benzoquinone was compared and contrasted to the same reaction catalyzed with Flextyl P, a novel Ti(IV) performance catalyst. The catalyst improved conversion by 22% versus the uncatalyzed reaction and represents a rare example of a Ti(IV) catalyzed Diels-Alder reaction in water.

Highlights

Traditional synthetic chemistry has acquired a wealth of information on the synthesis and structure of thousands of simple and complex molecules [1]
The aqueous DA reaction of 1,3-cyclohexadiene and p-benzoquinone were investigated according to the general methods of Kuroda et al (Scheme 1)
Upon addition of the catalyst, the aqueous solution of benzoquinone turns from golden yellow to olive green in color, indicating coordination of the dienophile with the Ti(IV) Lewis acid

Summary

Introduction

Traditional synthetic chemistry has acquired a wealth of information on the synthesis and structure of thousands of simple and complex molecules [1]. Four predominant strategies in the “green” approach to chemistry include: i) using water instead of organic solvents, ii) using solventless processes, iii) employing catalysts to enhance yield, reaction rate, as well as selectivity, and iv) promoting biosynthetic processes where appropriate [3]. The rates and stereoselectivities of Diels-Alder (DA) reactions are strongly affected by water [4].

Results

Conclusion