Exploring the Potential of Diarylacetylenediols as Hydrogen Bonding Catalysts

Abstract

In the course of a search for new classes of hydrogen bonding catalysts, we have examined diarylacetylenediols as potential catalysts for the Diels-Alder reaction. General and efficient methods have been developed for the preparation of these diols. Their structures were systematically modified and increased activity was observed for those possessing an electron-withdrawing group on the aryl groups. The electron-deficient diarylacetylenediol catalysts, while more active, undergo spontaneous cyclization to the corresponding benzo[b]furans. A mechanism is postulated to explain this facile transformation. Computational studies performed on 2-ethynylphenol help to explain the effect of the alkyne on the conformation and hydrogen bond donating ability of the adjacent OH group. Finally, the crystal structure of one of the diols is reported, and it displays an intricate network of intermolecular hydrogen bonds.

Investigation of the hydrogen bond donating ability of 1,8-naphthalenediol by NMR spectroscopy and its use as a hydrogen bonding catalyst

“…20−22 In 2013, the performance of diarylacetylenediols 23,24 (5) as phenol-based, dual hydrogen bonding catalysts was investigated by the Rawal group (Figure 1). 25 More recently, Ertürk and coworkers described the use of chiral HAROLs (6) as hydrogen bonding catalysts in Morita-Baylis-Hillman reactions and as ligands for the enantioselective addition reactions of organometallic compounds to aldehydes (Figure 1). 26 Despite the exciting developments in this area, discovery of new hydrogen bond donor scaffolds for * Correspondence: yeturkmen@bilkent.edu.tr This work is licensed under a Creative Commons Attribution 4.0 International License.…”

Scalable Biomimetic Syntheses of Paeciloketal B, 1-epi-Paeciloketal B, and Bysspectin A

“…Methoxymethyl (MOM) ether was chosen, since Turkmen and Rawal have demonstrated that diphenylacetylene diols can be prepared in excellent yield through deprotection of the corresponding MOM ethers with hydrochloric acid at room temperature. 17 Deprotection of known benzaldehyde 12 15 (previously prepared en route to 7) with boron tribromide according to the procedure described by Kingston and coworkers 18 afforded desired phenol 13 in good yield (2 g scale, Scheme 4). MOM protection of phenol 13 (gram scale), followed by a Grignard reaction with octylmagnesium bromide (2 g scale), afforded desired alcohol 14 in moderate yield alongside reduced benzyl alcohol 15.…”

“…A more labile protecting group was deemed necessary to allow for late stage removal under milder conditions. Methoxymethyl (MOM) ether was chosen, since Türkmen and Rawal have demonstrated that diphenylacetylene diols can be prepared in excellent yield through deprotection of the corresponding MOM ethers with hydrochloric acid at room temperature . Deprotection of known benzaldehyde 12 15 (previously prepared en route to 7 ) with boron tribromide according to the procedure described by Kingston and co-workers afforded desired phenol 13 in good yield (2 g scale, Scheme ).…”

Asimetrik Hetero Diels-Alder Reaksiyonu için Organaokatalizör Olarak Kiral 1,4-Hidroksiarilalkoller (HAROL) ve 1,4-Aminoalkilfenoller (AAP)

“…At this point, it should be noted that in 1985 Hine and co-workers already disclosed a nonasymmetric ring-opening reaction of phenyl glycidyl ether with diethylamine in the presence of 1,8-biphenylenediol as the catalyst [15]. Afterwards, there have also appeared other works in which phenols were used as HBD organocatalyst in particular cases [16,17].…”