Presentation Title

Gold Cavitands: Regioselective Ring Closing of Alkyne Acids

Faculty Mentor

Michael P. Schramm

Start Date

17-11-2018 10:00 AM

End Date

17-11-2018 10:15 AM

Location

C323

Session

Oral 2

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

Gold Cavitands: Regioselective Ring Closing of Alkyne Acids Teodora Nedic, Michael P. Schramm, Ph.D Department of Chemistry and Biochemistry, California State University-Long Beach, Long Beach, CA 90840

Gold cavitand usage and diversity in the transformations of small molecules have piqued the interest of our lab. Our gold cavitands in particular have varying wall sizes creating a sort of pocket in which we introduced monosubstituted alkyne acids of varying sizes to see whether or not a 5 or 6 membered cyclization occurred. Various analogs of alkyne acids were synthesized each with different R-group attachments to the end of the alkyne chain (ex. methyl, ethyl, and propyl groups). Upon introduction and reaction to the cavitand at room temperature and with heat, we anticipated some variation in the reactivity and cyclization patterns and we very much saw that. Each of the substrates cyclized, but they favored different products. For example, the substrate with a methyl R-group favored a 1:1 conversion of 5-membered and 6-membered rings. Conversely, the substrate with the propyl attachment favored 5-membered cyclization 9:1. These results were unexpected and were indicative of not only the size of the interior pocket but also which cyclization pattern is favored in general. To understand the nature of our gold cavitand, we will expand the collection of R-group substrates by varying the size and length of the analogs.

This project is supported in part by RISE (NIH 2R25GM071638-09A1) and NSF RUI (CHE 1708937)

Key words: gold, catalysis, organic synthesis, rings, lactones, cavitand, substrates

Summary of research results to be presented

The encompassing region of this research is to understand the capability of our lab's gold cavitand and it's influences on cyclizing alkyne monoacids. When introducing substrates of varying R-groups (methyl, ethyl, and propyl) to the inner reactive portion of the cavitand, we saw various cyclization patterns. For example, the substrate with the propyl attachment favored a 9:1 cyclization pattern of 5-membered to 6-membered rings where the methyl attachment favored a 50/50 slip of the two. With this knowledge we are beginning to see the size of the interior pocket and the types of reactions it favors.

This document is currently not available here.

Share

COinS
 
Nov 17th, 10:00 AM Nov 17th, 10:15 AM

Gold Cavitands: Regioselective Ring Closing of Alkyne Acids

C323

Gold Cavitands: Regioselective Ring Closing of Alkyne Acids Teodora Nedic, Michael P. Schramm, Ph.D Department of Chemistry and Biochemistry, California State University-Long Beach, Long Beach, CA 90840

Gold cavitand usage and diversity in the transformations of small molecules have piqued the interest of our lab. Our gold cavitands in particular have varying wall sizes creating a sort of pocket in which we introduced monosubstituted alkyne acids of varying sizes to see whether or not a 5 or 6 membered cyclization occurred. Various analogs of alkyne acids were synthesized each with different R-group attachments to the end of the alkyne chain (ex. methyl, ethyl, and propyl groups). Upon introduction and reaction to the cavitand at room temperature and with heat, we anticipated some variation in the reactivity and cyclization patterns and we very much saw that. Each of the substrates cyclized, but they favored different products. For example, the substrate with a methyl R-group favored a 1:1 conversion of 5-membered and 6-membered rings. Conversely, the substrate with the propyl attachment favored 5-membered cyclization 9:1. These results were unexpected and were indicative of not only the size of the interior pocket but also which cyclization pattern is favored in general. To understand the nature of our gold cavitand, we will expand the collection of R-group substrates by varying the size and length of the analogs.

This project is supported in part by RISE (NIH 2R25GM071638-09A1) and NSF RUI (CHE 1708937)

Key words: gold, catalysis, organic synthesis, rings, lactones, cavitand, substrates