Graduation Year

2022

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Chemistry

Major Professor

Xiaodong Micheal Shi, Ph.D.

Committee Member

James Leahy, Ph.D.

Committee Member

Jianfeng Cai, Ph.D.

Committee Member

Chuanhai Cao, Ph.D.

Committee Member

Libin Ye, Ph.D.

Keywords

Aldol Reaction, Alkyne Trifunctionalization, Gold Catalysis, Gold Redox Catalysis, Macrocyclization

Abstract

This dissertation mainly contains three parts: 1) the study of new reactivity of vinyl gold(I) and synergistic gold-iron catalyzed regioselective crossed aldol reaction. 2) synergistic gold-iron catalyzed amide crossed aldol reaction by using ynamides as ‘masked’ amides. 3) alkyne trifunctionalization via divergent gold catalysis: combining three modes of gold catalysis: π activation, nucleophilic addition of vinyl gold and gold redox catalysis. This novel method affords access to constructing C-N, C-O and C-C bond in one step at mild condition.

In the first part, a new reaction mode in gold catalysis will be introduced. Due to the protodeauration of vinyl gold (I), the reactivity of vinyl gold has rarely been explored. Here we reported the first example of vinyl gold nucleophilic addition to carbonyl compounds. To block the rapid protodeauration, Fe(acac)3 was applied in the reaction, which effectively block the protodeauration pathway and facilitated the vinyl gold(I) nucleophilic addition to aldehydes/ketones. The directing group boosted the reactivity and increased the rigidity of vinyl gold intermediate, which allowed macrocyclization at mild conditions with no dilution. This application highlighted novelty and usefulness of this transformation in organic synthesis.

In the second part, synergistic gold-iron catalyzed yamide crossed aldol reaction and will be discussed. One of the limitations of our previous work was the employment of directing group. Ynamides were found to have the similar reactivity. Crossed aldol reaction between amides and other carbonyl compounds has rarely been reported because amides are not good aldol donors. Ynamides, a surrogate for amides, were applied in the crossed aldol reaction with high yields at mild conditions via synergistic gold-iron catalysis.

In the third part, alkyne trifunctionalization will be presented. Three catalysis modes of gold were employed to introduce three functionalities into alkyne in one step. A compatible combination of π-activation, vinyl gold nucleophilic addition and gold redox catalysis is the key to the success of this reaction where aryl diazonium salts served as electrophile (N source) and oxidant (C source).

In summary, new reaction modes in gold catalysis with the first example of vinyl gold nucleophilic addition was presented herein. Based on this discovery, the first example of alkyne trifunctionalization by integrating three gold catalysis modes was achieved. The newly developed access to vinyl gold(I) and vinyl gold(III) will facilitate more useful transformations in gold catalysis.

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