Thallium trinitrate application in the preparation of indanes and in the total synthesis of mutisianthol

Author(s)

Andréa Maria Aguilar

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2003-05-08

Examining board members

Helena Maria Carvalho Ferraz; Fernando Antônio Santos Coelho; Liliana Marzorati; José Ricardo Romero; Hans Viertler

• Advisor: Helena Maria Carvalho Ferraz

Abstract

This thesis presents the first synthetic application of the methodology developed in our research group, which involves the ring contraction of 1,2- dihydronaphthalenes promoted by thallium trinitrate (TTN) to afford indane derivatives. The target molecule of the synthetic approach is Mutisianthol, a phenolic sesquiterpene, isolated from Mutisia homoeantha in 1979, which embodies a trans-1,3-disubstituted cyclopentyl unit. The proposed route was first optimized in the synthesis of a model compound and then applied to the total synthesis of Mutisianthol. The starting material chosen for the Mutisianthol synthesis was the commercially available and cheap 2-methyl-anisol. The key step of the sequence involved the ring contraction of the 1,6-dimethyl-7-methoxy-1,2-dihydronaphthalene promoted by TTN, which furnished a functionalized indan with good yield and with high diastereoselectivity. The indan derivative was transformed into the final product in 3 steps. Overall, the total synthesis of Mutisianthol was accomplished in 12 steps. The TTN- promoted ring contraction of a series of 1-tetralones and of 1,2- dihydronaphthalenes was also studied in this thesis, with the aim to prepare other indanes and to extend earlier studies. (AU)