A One-Pot Reaction toward the Diastereoselective Synthesis of Substituted Morpholines
作者:Thomas Aubineau、Janine Cossy
DOI:10.1021/acs.orglett.8b03141
日期:2018.12.7
The diastereoselectivesynthesis of various substituted morpholines has been achieved from vinyloxiranes and amino-alcohols under sequential Pd(0)-catalyzed Tsuji–Trost/Fe(III)-catalyzed heterocyclization. Using the same strategy, 2,6-, 2,5-, and 2,3-disubstituted as well as 2,5,6- and 2,3,5-trisubstituted morpholines were obtained in good to excellent yields and diastereoselectivities.
The chloroallyl zinc reagent generated insitu by deprotonation of allyl chloride in the presence of lithium diisopropylamide and zinc chloride undergoes highly regio- and diastereoselective α-addition to carbonyl compounds to give syn chlorohydrins which on treatment with base afford cis vinyloxiranes in high yields.
In the presence of solid KOH, allyldi-isobutyltelluroniumbromide 2 reacts directly with aromatic aldehydes at room temperature under solid–liquid phase-transfer conditions to afford α,β-unsaturatedepoxides 3 in excellent yields.