Hydrolysis of Iminium Ethers Derived from the Reaction of Ketones with Hydroxy Azides: Synthesis of Macrocyclic Lactams and Lactones
作者:Jennifer E. Forsee、Jeffrey Aubé
DOI:10.1021/jo990041h
日期:1999.6.1
The hydrolysis of iminium ether intermediates formed by a nitrogen insertion sequence involving azido alcohols 1 or 2 and ketones was investigated. Ketones containing 6-12-membered rings were surveyed and shown to provide lactams and lactones in good to excellent overall yield. Reactions employing acetone or 5-nonanone gave similar results, generating analogous amides and esters. The relative amounts of lactone vs lactam produced in a given reaction were found to depend on the structures of the reactants and the pH of the basic media used to hydrolyze the iminium ethers. A mechanism accounting for the formation of each product is discussed in terms of ring strain and the protonation state of ortho ester animal intermediates.
Remodeling and Enhancing Schmidt Reaction Pathways in Hexafluoroisopropanol
作者:Hashim F. Motiwala、Manwika Charaschanya、Victor W. Day、Jeffrey Aubé
DOI:10.1021/acs.joc.5b02764
日期:2016.2.19
The effect of carrying out two variations of the Schmidt reaction with ketone electrophiles in hexafluoroisopropanol (HFIP) solvent has been studied. When TMSN3 is reacted with ketones in the presence of triflic acid (TfOH) promoter, tetrazoles are obtained as the major products. This observation is in contrast to established methods, which usually lead to amides or lactams arising from formal NH insertion