Thermodynamic Control of Diastereoselectivity in the Formal Nucleophilic Substitution of Bromocyclopropanes
作者:Joseph E. Banning、Anthony R. Prosser、Michael Rubin
DOI:10.1021/ol100187c
日期:2010.4.2
A new, general, and chemoselective protocol for the formal nucleophilic substitution of 2-bromocyclopropylcarboxamides Is described. A wide range of alcohols and phenols can be employed as pronucleophiles in this transformation, providing expeditious access to trans-cyclopropanol ethers. A new mode of the selectivity control through a thermodynamic equilibrium is realized, alternative to the previously described steric and directing modes.
Diastereoselectivity Control in Formal Nucleophilic Substitution of Bromocyclopropanes with Oxygen- and Sulfur-Based Nucleophiles
作者:Joseph E. Banning、Anthony R. Prosser、Bassam K. Alnasleh、Jason Smarker、Marina Rubina、Michael Rubin
DOI:10.1021/jo200368a
日期:2011.5.20
diastereoconvergent formal nucleophilicsubstitution of bromocyclopropanes with oxygen- and sulfur-based nucleophiles is described. The reaction proceeds via in situ formation of a highly reactive cyclopropene intermediate and subsequent diastereoselective addition of a nucleophile across the strained C═C bond. Three alternative means of controlling the diastereoselectivity of addition have been demonstrated: