From Pyridiniums to Chiral Amines

Congratulations to Kristen Baker, Amanda Tallon (Fox Research Group), Olivia Bercher, and our Pfizer collaborators Matt Perry and Richard Loach on their method to prepare α-chiral amines via  the reaction of alkylpyridinium salts and sulfinimines (link)! It’s our first foray into non-nickel catalyzed reactions of alkylpyridinium salts, and proceeds via a rare thermally promoted SET of an anion–π complex of the pyridinium and carbonate anion.

Converting NH2 to CH3

Congratulations to Olivia Bercher, Shane Plunkett, and Tom Mortimer for their development of a nickel-catalyzed reductive methylation of alkylpyridinium salts (link)! This method enables amino groups to be converted into methyls via pyridinium salt intermediates.

New Route to Alkyl Nitriles

Congratulations to Jianyu Xu and Cameron Twitty on their report of a nickel-catalyzed cya nation of alkylpyridinium salts (link)! Now chemists can transform alkyl amines to nitriles and perform one-carbon homologations without complete resynthesis.

Congratulations, Dr. Kristen Baker!

Congratulations, Dr. Kristen Baker, on defending your thesis, “Deaminative Couplings of Alkylpyridinium Salts!” Great research and great story. It was also super special to celebrate in person! We miss you already and wish you all the best in your postdoc at Providence College!!

Understanding How Pyridinium Structure Influences Deamination

In this collaborative effort with the Kozlowski and Rosenthal groups, we investigate the effect of pyridinium substituents on the efficiency of reduction and C–N bond cleavage. You may have wondered if those 2,6-aryl groups were really needed… This paper answers that question and then delves deeper into the electronic and steric factors that promote deamination. We learned so much in this collaboration and are excited to see it published in ACS Catalysis.

New Method for Stereospecific Quat Center Formation

We’re so excited to see Jianyu and Olivia’s work published (link)! Jianyu discovered that the addition of a stilbene enables stereospecific cross-couplings of benzylic carboxylates without naphthyl substitution! Olivia’s mechanistic studies show that there’s more to learn about this intriguing catalyst system (more to come on that). Congrats to Jianyu and Olivia!

New Artwork

Thanks to the fabulous Samantha Santana for our new group portrait! We love this new header image (and the way you captured our personalities)!!

Enantioselective Alkynylation of Unstabilized Cyclic Iminium Ions

Weiye Guan, Samantha Santana, Jennie Liao, and Kelci Henninger have developed a highly enantioselective, copper-catalyzed alkynylation of unstabilized cyclic iminium ions (link). This reaction delivers alpha-chiral amine heterocyclic with easily deprotected nitrogen protecting groups. The key was squeezing the chiral pocket by adding ethyl groups to the PyBox ligand. Congratulations to the team for this great method!

Also unveiling Sam’s awesome artwork celebrating Weiye’s discoveries and PhD!

Congratulations, Dr. Jianyu Xu!

Congratulations, Dr. Jianyu Xu, on defending your thesis, “Nickel-Catalyzed Cross-Couplings via Activation of Carbon–Oxygen and Carbon–Nitrogen Bonds!” It was great to celebrate your accomplishments and reminisce on how wonderful it has been to work with you!!

Congratulations, Dr. Weiye Guan!

Congratulations, Dr. Weiye Guan, on defending your thesis, “Catalytic Reactions of Pyridinium and Iminium Ions.” We loved celebrating your accomplishments with a virtual gathering. We wish you all the best in your next position at Adesis! We will miss you!!!

Congratulations, Dr. Megan!

Congratulations, Dr. Megan Hoerrner, on defending your thesis “Nickel-Catalyzed Cross-Coupling Reactions Through C–O and C–N Bond Activation.” This is the 11th PhD defense from the group, and our first one via Zoom videoconference! Best wishes for your next position at Vertex Pharmaceuticals! We miss you!!

Congratulations, Dr. Javon!

Congratulations, Dr. Javon Rabb-Lynch, on defending your thesis “Suzuki–Miyaura Cross-Couplings of Allylic Pivalates to Access All-Carbon Quaternary Stereocenters.” Best wishes for your postdoc at the Naval Research Labs!! We’ll miss you (and all your jokes)!


Our Latest Pyridinium Papers

Congratulations to Megan Hoerrner, Kristen Baker, Corey Basch, and Earl Bampo for their Deaminative Arylation of Amino Acid-derived Pyridinium Salts! This method enables amino acids to be converted to propionic acid derivatives.

Congrats also to Kristen Baker, Diana Lucas Baca, Shane Plunkett, and Mitchell Daneker for their alkyl–alkyl cross-coupling of pyridinium salts with alkyl boranes generated in situ from alkene hydroboration! We submitted this one on Halloween, so Mitchell celebrated with a hot chocolate and dressing as a Dixie cup (see photo).

Reductive Couplings of Alkylpyridinium Salts

In collaboration with Michelle Garnsey, Brian Boscoe, and Joe Tucker at Pfizer, Inc., Jennie Liao, Corey Basch, Megan Hoerrner, and Mike Talley developed a reductive cross-electrophile coupling of alkylpyridinium salts with aryl bromides (link). Congratulations to the team for their great work! Congrats also to Prof. Ruben Martin’s team, who developed a similar reaction (link)!

Alkyl–Alkyl Cross-Coupling Highlighted in OPRD

Group members Shane Plunkett, Corey Basch, and Samantha Santana have developed a Negishi alkylation of alkylpyridinium salts. This is the first example of alkyl–alkyl cross-coupling of alkylpyridinium salts with unactivated alkyl groups. Read it all in their J. Am. Chem. Soc. paper (link). This work was highlighted in Org. Process Res. Dev. Congratulations to this team for a great new reaction!