Synthesis of highly substituted 2,6-anti-configured tetrahydropyrans. First steps towards an efficient access to amphidinol 3 ring system
摘要:
Highly functionalised and polysubstituted tetrahydropyrans, akin to the middle core of the amphidinols, can be efficiently synthesised, with full stereocontrol and in good yields, using as key steps an anti-allylation reaction coupled with an intramolecular Sakurai cyclisation. Three approaches were devised in order to reach a broad range of substitution patterns. (c) 2005 Elsevier Ltd. All rights reserved.
[1,5]-Brook rearrangement: an overlooked but valuable silyl migration to synthesize configurationally defined vinylsilane. The unique steric and electronic effects of geminal bis(silane)
geminal bis(silyl) homoallylic alcohol is described. The unique steric and electroniceffects of geminal bis(silane) were found to be crucial for promoting this long-range silyl migration, as well as for facilitating the subsequent gamma/Z-selective addition of silyl allyllithium with carbonyl compounds to synthesize diverse configurationally defined Z-vinylsilanes.
Reactions of 3-tributylstannyl-2-(trimethylsilylmethyl)propene with acid chlorides or aldehydes proceed smoothly without any catalytic activation to afford allylsilanes bearing various functionalities.
Synthesis of highly substituted 2,6-anti-configured tetrahydropyrans. First steps towards an efficient access to amphidinol 3 ring system
作者:Christophe Dubost、Istvan E. Markó、Justin Bryans
DOI:10.1016/j.tetlet.2005.04.041
日期:2005.6
Highly functionalised and polysubstituted tetrahydropyrans, akin to the middle core of the amphidinols, can be efficiently synthesised, with full stereocontrol and in good yields, using as key steps an anti-allylation reaction coupled with an intramolecular Sakurai cyclisation. Three approaches were devised in order to reach a broad range of substitution patterns. (c) 2005 Elsevier Ltd. All rights reserved.
Preparation and Synthetic Utility of 2-Methylselenomethyl Allyl Methyl Selenide. A Valuable Precursor to 2-Silylmethylallyllithiums
作者:Alain Krief
DOI:10.1055/s-1998-1915
日期:1998.11
3-Lithio-2-[silylmethyl]propenes, easily prepared from 3-methylseleno-2-[silylmethyl]propenes by the cleavage of the C-Se bond, are useful intermediates for the preparation of a variety of functionalised allylsilanes. These allylsilanes are interesting building blocks, used for example, as annelating agents in the efficient synthesis of spiroketals by the Intramolecular Silyl-Modified Sakurai (ISMS)