Yu-Lin Tsai

Synthesis of Substituted 1,6-Diarylnaphthalenes via a Tandem Claisen Rearrangement and Ene Reaction Protocol

In this work, we developed a concise synthetic route for the synthesis of polysubstituted naphthalenes starting from commercially available isovanillin and its derivatives. Reaction with styryl bromide via O-styrylation, Claisen rearrangement, ene reaction, and O-alkylation occurred in high yields. The key structures were confirmed by single-crystal X-ray diffraction.

Construction of Nitrated Benzo[3.3.1]bicyclic Acetal/Ketal Core via Nitration of o-Carbonyl Allylbenzenes

Intramolecular annulation of o-carbonyl allylbenzenes was achieved to construct novel nitrated [6,6,6]tricycles having an acetal or ketal motif in good yields. The expeditious one-step nitration route provides 4 or 5 new bond formations, including 2 or 3 C-N bonds and 2 C-O bonds. The structural framework of benzobicycle [3.3.1] is confirmed by X-ray crystallographic analysis. A plausible mechanism is proposed.

Bi(OTf)3-Mediated Intramolecular Olefinic Cyclization: Synthesis of Substituted Aryl-Dihydronaphthalenes and Indenes

In this article, a facile two-step and one-pot synthetic route for the preparation of substituted aryl dihydronaphthalenes starting from 2-allylbenzaldehydes via Grignard 1,2-addition and Bi(OTf)3-catalyzed intramolecular olefinic cyclization has been developed. A five-membered ring indene skeleton is also prepared via olefin isomerization, 1,2-addition followed by cyclization. Some key structures are determined using single-crystal X-ray crystallography. A possible mechanism is presented herein.

One-Pot Synthesis of 2-Cyano-1,4-diketones: Applications to Synthesis of Cyanosubstituted Furans, Pyrroles, and Dihydropyridazines

A convenient synthetic route for the construction of functionalized 2-cyano-1,4-diketones has been established from the nucleophilic substitution of 2-bromoacetophenones with NaCN via the in situ-generated β-ketonitriles. This method was further applied to the synthesis of cyanosubstituted furans, pyrroles, or dihydropyridazines, which were obtained in good to excellent yields using Bi(OTf)3, NH4OAc, or N2H4. The key structures were confirmed by X-ray single crystal diffraction analysis.

CuI Mediated One-Pot Cycloacetalization/Ketalization of o-Carbonyl Allylbenzenes: Synthesis of Benzobicyclo[3.2.1]octane Core

CuI/DMSO-mediated intramolecular cycloacetalization/ketalization of o-carbonyl allylbenzenes has been achieved for constructing [6,6,5]-tricycles having a ketal motif in good yields. The expeditious one-step route provides a three C-O bond formation. The key products with the structural framework of a benzofused dioxabicyclo[3.2.1]octane core have been confirmed by X-ray crystallographic analysis. Synthesis of dihydroisocoumarin has been studied.

Metal triflate promoted synthesis of naphthalenes

A synthetic route to derive the skeleton of naphthalenes starting with isovanillin is described with modest total yields via the key transformation of metal triflate-mediated intramolecular benzannulation of o-formyl or o-benzoyl allylbenzenes in MeNO2 at rt.