New camphor-derived sulfur chiral controllers: Synthesis of (2R-exo)-10-methylthio-2-bornanethiol and (2R-exo)-2,10-bis(methylthio)bornane
摘要:
An efficient preparation of two camphor-derived controllers [(2R-exo)-10-methylthio-2-bornanethiol 1b and (2R-exo)-2,10-bis(methylthio)bornane 2] potentially useful as a ligands or chiral auxiliaries in asymmetric synthesis is described. Both compounds have been prepared starting from (1S)-camphor-10-thiol 3. Alkylation of this thiol with sodium methoxide and methyl iodide afforded 10-methylthiocamphor 8. Conversion of 8 into the corresponding thioketone 9 with the Lawesson's reagent followed by the stereoselective reduction with DIBAL-H at low temperature yielded (2R-exo)-10-methylthio-2-bornanethiol 1b in good yield. (2R-exo)-2,10-bis(Methylthio)bornane 2 could be obtained by alkylation of 1b with sodium methoxide and methyl iodide. Copyright (C) 1996 Elsevier Science Ltd.
Asymmetric Pauson−Khand Reactions Using Camphor-Derived Chelating Thiols as Chiral Controllers
作者:Iolanda Marchueta、Elvira Montenegro、Dmitri Panov、Marta Poch、Xavier Verdaguer、Albert Moyano、Miquel A. Pericàs、Antoni Riera
DOI:10.1021/jo015790p
日期:2001.9.1
(1S)-camphor-10-thiol has been developed. The ethynyl derivatives of these thiols gave excellent diastereoselectivities (up to 98:2) in Pauson-Khandreactions with norbornene and norbornadiene through the intermediacy of a chelated dicobalt pentacarbonyl complex. Thermal reaction conditions starting from the preformed chelated complex gave better results than N-oxide-promoted runs with in situ generation of
New camphor-derived sulfur chiral controllers: Synthesis of (2R-exo)-10-methylthio-2-bornanethiol and (2R-exo)-2,10-bis(methylthio)bornane
作者:Elvira Montenegro、Raouf Echarri、Carmen Claver、Sergio Castillón、Albert Moyano、Miquel A Pericàs、Antoni Riera
DOI:10.1016/s0957-4166(96)00463-6
日期:1996.12
An efficient preparation of two camphor-derived controllers [(2R-exo)-10-methylthio-2-bornanethiol 1b and (2R-exo)-2,10-bis(methylthio)bornane 2] potentially useful as a ligands or chiral auxiliaries in asymmetric synthesis is described. Both compounds have been prepared starting from (1S)-camphor-10-thiol 3. Alkylation of this thiol with sodium methoxide and methyl iodide afforded 10-methylthiocamphor 8. Conversion of 8 into the corresponding thioketone 9 with the Lawesson's reagent followed by the stereoselective reduction with DIBAL-H at low temperature yielded (2R-exo)-10-methylthio-2-bornanethiol 1b in good yield. (2R-exo)-2,10-bis(Methylthio)bornane 2 could be obtained by alkylation of 1b with sodium methoxide and methyl iodide. Copyright (C) 1996 Elsevier Science Ltd.