Metal-free and environmentally friendly synthesis of morpholin-3-one and 1,4-oxazepan-3-one skeletons was achieved by the cycloaddition reaction of alcohol-tethered enones and α-halohydroxamates. This transformation was proposed to proceed through the addition of the hydroxyl group

A metal and catalyst-free, environmentally friendly synthesis of hindered dialkyl ether derivatives has been established via the nucleophilic alkoxylation of alcohols and α-halohydroxamates. The reactions of a variety of primary and secondary alcohols with azaoxyallyl cations generated in situ from α-halohydroxamates afforded a wide range of hindered dialkyl ether derivatives in good yields. Moreover, methods for the synthesis of α-alkoxyhydroxamic acids, α-alkoxy amides, and α-hydroxy amides from αalkoxy hydroxamates were established. [a] E. Scheme 1. Representative examples of hindered dialkyl ether synthesis. Scheme 2. Nucleophilic amination and alkoxylation of α-bromohydroxamate.

Organocatalytic enantioselective intramolecular oxa-Michael reactions of benzyl alcohol bearing α,β-unsaturated carbonyls as Michael acceptors are presented herein. Using cinchona squaramide-based organocatalyst, enones as well as α,β-unsaturated esters containing benzyl alcohol provided their corresponding 1,3-dihydroisobenzofuranyl-1-methylene ketones and 1,3-dihydroisobenzofuranyl-1-methylene esters in excellent yields with high enantioselectivities. In addition, enantioenriched 1,3-dihydroisobenzofuranyl-1-methylene ketone could be obtained from the Wittig/oxa-Michael reaction cascade of 1,3-dihydro-2-benzofuran-1-ol.

An enantioselective synthetic method for 1‐substituted phthalans has been developed. The organocatalytic reaction between 1,3‐dihydro‐2‐benzofuran‐1‐ols and Wittig reagents using cinchona squaramide‐based organocatalyst proceeded with sequential Wittig reaction followed by an enantioselective intramolecular oxa‐Michael reaction, yielding enantioenriched phthalans with moderate to good enantioselectivities.