Diastereoselective Alkylations of Oxazolidinone Glycolates: A Useful Extension of the Evans Asymmetric Alkylation
作者:Michael T. Crimmins、Kyle A. Emmitte、Jason D. Katz
DOI:10.1021/ol006091m
日期:2000.7.1
[GRAPHICS]The diastereoselective alkylation of glycolate oxazolidinones has been demonstrated as a method for the enantioselective preparation of alpha-alkoxy carboxylic acid derivatives and selectively protected 1,2-diols, Various protecting groups on the glycolate hydroxyl and multiple substitution patterns on allylic iodides are tolerated in the alkylation, Yields for the alkylations are typically 70-85% with diastereoselectivities of >98:2.
An Efficient Strategy for the Synthesis of α,α′-cis and trans-Disubstituted Medium Ring Ethers
作者:Michael T. Crimmins、Kyle A. Emmitte
DOI:10.1055/s-2000-6268
日期:——
An asymmetric alkylation-ring-closing metathesis strat- egy was developed for the construction of a,a'-disubstituted medi- um ring ethers. The approach features an asymmetric alkylation of highly functionalized a-alkoxy acyl oxazolidinones followed by ring closure effected by Grubbs ' ruthenium catalyst. The relation- ship between diene conformation and the rate of ring-closure was examined.