1,1-Diboration paper accepted in Org. Lett.

Yang and Zhong-Qian’s paper describing the copper-catalyzed conversion of the terminal alkynes to stereodefined 1,1-diborylalkenes has been accepted in Org. Lett. and appears in final form online today. Mechanistically, the reaction involves a tandem sequence of dehydrogenative C(sp)–H borylation with HBdan followed by hydroboration with HBpin with copper playing a dual role as catalyst for both steps. Preparatively, the method enables one-step access to valuable alkyl- and aryl-substituted 1,1-diborylalkenes, which can then be further diversified through sequential cross-coupling. Congrats to postdoc Yang and undergrad co-author Zhong-Qian!

For a link to the paper, click here: https://pubs.acs.org/doi/full/10.1021/acs.orglett.0c01901

This work was first described in April in a pre-print that was deposited on ChemRxiv: https://chemrxiv.org/articles/Synthesis_of_Stereodefined_1_1-Diborylalkenes_via_Copper-Catalyzed_Diboration_of_Terminal_Alkynes/12133404

Alkene [3+2]-(Hetero)annulation Pre-print Online

We kick off the post-Father’s-Day workweek with a new pre-print on ChemRxiv describing the application of our lab’s strategy for directed nucleopalladation of alkenes to the synthesis of carbo- and heterocycles via [3+2]-(hetero)annulation. Though the mechanistic details are rather different, this reaction takes inspiration from the venerable Larock indole synthesis, enabling access to diverse indolines, 2,3-dihydrobenzofurans, and indanes from readily available starting materials. Working in close collaboration with Pfizer’s Oncology Medicinal Chemistry team and the Liu group at the University of Pittsburgh, we were able to examine a broad swath of a heterocyclic structural space relevant to drug discovery and to flesh out the reaction mechanism. Congrats to this fantastic team of coworkers: Hui-Qi, Pranali, and Hou-Xiang from our lab; Joyann, Shouliang, Michelle and Indra from Pfizer; and Ilia and Peng from Pitt. Special shout-out to our two undergraduate co-authors Pranali and Hou-Xiang!

For a link to the pre-print, click here: https://chemrxiv.org/articles/Anti-Selective_3_2_Hetero_annulation_of_Non-Conjugated_Alkenes_via_Directed_Nucleopalladation/12510038

The Engle Lab turns 5

Today we celebrate our 5 year Lab-iversary! Rather than our normal tradition of eating lunch and cake together, this year we celebrated social-distancing-style, with cupcakes and online games. Our first five years as a lab at Scripps have gone quickly, with plenty of highs, lows, and interesting discoveries along the way. Here’s to the next 5!