Professor Cho’s research deals generally with total synthesis of bioactive natural products and development of new synthetic methods. During the past few years, His research group has explored the Diels-Alder chemistry of a new enophile synthon 3,5-dibromo-2-pyrone.
Its synthetic versatility has been further exuberated by the recent discovery that either of the two C-Br groups can be selectively functionalized through transition metal catalyzed coupling reactions. The resultant 3- or 5-substituted 2-pyrones are also potent neutral dienes, and can undergo cycloaddition reaction to afford an array of densely functionalized cyclohexenes.
Ever since then, his research group has explored the potential applicability of the rich chemistry embedded in the 2-pyrone cycloadducts, toward the synthesis of complex bioactive natural products, resulting in total syntheses of trans-dihydronarciclasine, joubertinamine, mesembrine, crinine, crinamine, galanthamine, aspidospermidine, pancratistatin, α-lycorane and lycorine Professor Cho’s group has also discovered that aryl hydrazides are effective surrogates of aryl hydrazines, undergoing various reactions including the Fischer indolization reaction to afford the corresponding indoles, when treated with aldehydes or ketones in the presence of an acid. Unlike aryl hydrazines, the aryl hydrazides are readily accessed from aryl halides via the Pd(0) or Cu(I)-catalyzed coupling reaction with N-Boc hydrazine. Also reported was that N-Cbz-aryl hydrazide can proceed in a Fischer indolization reaction to give N-Cbz-indole without the elimination of N-Cbz group.
More recently his group has found that aryl hydrazide with carbonyl function tethered at the C(4) position of the aromatic ring undergoes intramolecular Fischer indolization to afford novel indolophanes. The strategic insertion of a double bond in the tether allowed for an aromatic Claisen rearrangement to proceed in a tandem fashion, providing a ready access to various tricyclic benzo[cd]indole system.
Its synthetic versatility has been further exuberated by the recent discovery that either of the two C-Br groups can be selectively functionalized through transition metal catalyzed coupling reactions. The resultant 3- or 5-substituted 2-pyrones are also potent neutral dienes, and can undergo cycloaddition reaction to afford an array of densely functionalized cyclohexenes.
Ever since then, his research group has explored the potential applicability of the rich chemistry embedded in the 2-pyrone cycloadducts, toward the synthesis of complex bioactive natural products, resulting in total syntheses of trans-dihydronarciclasine, joubertinamine, mesembrine, crinine, crinamine, galanthamine, aspidospermidine, pancratistatin, α-lycorane and lycorine Professor Cho’s group has also discovered that aryl hydrazides are effective surrogates of aryl hydrazines, undergoing various reactions including the Fischer indolization reaction to afford the corresponding indoles, when treated with aldehydes or ketones in the presence of an acid. Unlike aryl hydrazines, the aryl hydrazides are readily accessed from aryl halides via the Pd(0) or Cu(I)-catalyzed coupling reaction with N-Boc hydrazine. Also reported was that N-Cbz-aryl hydrazide can proceed in a Fischer indolization reaction to give N-Cbz-indole without the elimination of N-Cbz group.
More recently his group has found that aryl hydrazide with carbonyl function tethered at the C(4) position of the aromatic ring undergoes intramolecular Fischer indolization to afford novel indolophanes. The strategic insertion of a double bond in the tether allowed for an aromatic Claisen rearrangement to proceed in a tandem fashion, providing a ready access to various tricyclic benzo[cd]indole system.