Rearrangement of Homoallylic Alcohols with Thallium(III): Diastereoselective Synthesis of Indans Bearing a β-Hydroxy Ketone Moiety. -The Tl(III)-mediated ring contraction of dihydronaphthalenes containing a suitably positioned hydroxyl group is examined. The rearrangement occurs in a diastereoselective manner. -(SILVA*, L. F. J.; QUINTILIANO, S. A. P.; CRAVEIRO, M. V.; VIEIRA, F. Y. M.; FERRAZ, H. M. C.; Synthesis 2007, 3, 355-362; Inst. Quim., Univ. Sao Paulo, 05513 Sao Paulo, Brazil; Eng.) -Mais 21-081
Terpenes
Terpenes U 0200Model Studies Toward the Synthesis of Natural Indans Utilizing a Thallium(III)-Mediated Ring-Contraction Reaction. -A mechanism for the first key step, a thallium(III)-promoted ring contraction reaction of the 1,2-dihydronaphthalene (II), is discussed. A second key step is Wittig olefination of methyl ether (V) to attach the side chain. The product (VIII) serves as a model compound for the sesquiterpenes mutisianthol (IXa) and jungianol (IXb). -(FERRAZ*, H. M. C.; AGUILAR, A. M.; SILVA, L. F. J.; Synthesis 2003, 7, 1031-1034; Inst. Quim., Univ. Sao Paulo, 05513 Sao Paulo, Brazil; Eng.) -C. Herrmann 41-187
Room Temperature, Metal-Free Synthesis of Diaryl Ethers with Use of Diaryliodonium Salts. -A wide range of diaryl ethers including bulky ortho-substituted ones is prepared. The etherification proceeds without racemization. -(JALALIAN, N.; ISHIKAWA, E. E.; SILVA, L. F. J.; OLOFSSON*, B.; Org. Lett. 13 (2011) 6, 1552-1555, http://dx.doi.org/10.1021/ol200265t ; Dep. Org. Chem., Arrhenius Lab., Univ. Stockholm, S-106 91 Stockholm, Swed.; Eng.) -Jannicke 25-062
Alkaloids U 0600 A Diastereoselective Total Synthesis of trans-Trikentrin A (VIII): A Ring Contraction Approach. -(SILVA*, L. F. J.; CRAVEIRO, M. V.; Org. Lett. 10 (2008) 23, 5417-5420; Inst. Quim., Univ. Sao Paulo, 05513 Sao Paulo, Brazil; Eng.) -Lindner 17-195
With a view to the preparation of cycloalkylindole alkaloid structures such as cis-trikentrin A (I) for biological studies, optimized conditions concerning the formation of the tricyclic skeleton are developed. They render possible the ring contraction of cyclohexene moiety to a functionalized cyclopentene unit. -(SILVA*, L. F. J.; CRAVEIRO, M. V.; GAMBARDELLA, M. T. P.; Synthesis 2007, 24, 3851-3857; Inst. Quim., Univ. Sao Paulo, 05513 Sao Paulo, Brazil; Eng.) -Mais 20-106
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Ring Contraction Strategy Toward a Diastereoselective Total Synthesis of (+)-Bakkenolide A (VII). -The key steps are a ring contraction of the octalone (I) and stereoselective formation of the keto ester (VI). In connection with the investigations concerning the contraction, the structure of a levorotary trinorsesquiterpene, isolated from Senecio humillimus, is revised from (S,S) to (R,R)-(VIII). -(CARNEIRO, V. M. T.; FERRAZ, H. M. C.; VIEIRA, T. O.; ISHIKAWA, E. E.; SILVA*, L. F.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.