The oxidative carbonylation of aniline to N,N′‐diphenylurea was carried out by using W(CO)6 as the catalyst, I2 as the oxidant, CO as the carbonyl source and 4‐(dimethylamino)pyridine (DMAP) as base. The reaction conditions were optimized with respect to different bases, molar ratio of DMAP/iodine, temperature, time, and CO pressure. Various p‐substituted arylamines can be converted into the respective symmetrical and unsymmetrical N,N′‐disubstituted ureas in moderate to good yields. The reaction demonstrated broad tolerance of functionality.
Allenyl esters activated
by titanium(IV) underwent additions to a wide range of aldehydes in
high regio- and diastereoselectivities leading to products containing
an all-carbon quaternary center bearing an α-vinyl group that
was installed with high selectivity for the Z-geometry.
An aldol product was also converted to an indanone offering a new
route to this important compound class. Product triple diastereoselectivity
has been rationalized using a concerted transition-state model.
Title carbonylation reaction of a wide variety of aromatic amines (I) with carbon monoxide is smoothly achieved in the system iodine—DMAP—W(CO)6 to give symmetrical diarylurea derivatives (III).
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