The Stereochemistry of Organometallic Compounds. XLIII. Rhodium-Catalysed Reactions of 2-(Alkenyloxy)benzylamines and 2-(N-Allyl-N-benzylamino)benzylamine

Abstract

Reactions of 2-( allyloxy ) benzylamines with H2/CO in the presence of rhodium catalysts give 1,3-benzoxazines, and 2-(N- allyl-N-benzylamino ) benzylamine gives a quinazoline . These reactions have been shown to involve allylic cleavage followed by regioselective carbonylation at the internal carbon atom as demonstrated by crossover experiments. Reactions of longer chain ( alkenyloxy ) benzylamines under similar conditions give polymeric material.

Ring forming reactions of imines of 2-aminobenzaldehyde and related compounds

“…After addition of 100 mL water, the product was filtered off and dried to yield 9.89 g (47.5 mmol, 95%) white powder, mp 118 ЊC (lit. 30 mp 117-118 ЊC).…”

High yields of diazabicycloalkanes and oxazabicycloalkanes containing medium and large rings from rhodium-catalysed hydroformylation reactions without the need for high dilution conditions

“…There is indirect evidence that iminium species contained in medium or large rings are susceptible to polymerisation reactions. 3 Thus the possibility that a pendant amino or hydroxy function could be used to trap any such reactive cyclic iminium species was investigated as a general route to the synthesis of bicyclic heterocycles containing medium or large rings.…”

Synthesis and Fungicidal Activity of Novel 2,3-Disubstituted-1,3-benzoxazines

“…3,4-dihydro-2 H -1,3-benzoxazines exhibit a wide range of biological activity [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ], such as bactericidal, fungicidal, antitumour, antituberculosis, and anthelmintic effects, therefore, the synthesis of these compounds has attracted great interest. Several elegant methods for the preparation of these compounds have been documented in the literature [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Burke and co-workers disclosed a Mannich-type condensation of phenols with primary amines and formaldehyde to provide 2-unsubstituted 3,4-dihydro-2 H -1,3-benzoxazines [ 5 , 12 , 13 , 14 ].…”

“…It was noted that condensation reactions could be operated without catalyst, but sometimes a catalyst such as TsOH or triethylamine was necessary. Recently, rhodium-catalyzed reactions of 2-(alkenyloxy)benzylamines which involve an allylic cleavage followed by regioselective carbonylation at the internal carbon atom have been developed as a new way to generate 3,4-dihydro-1,3-benzoxazines [ 19 , 20 ]. Despite these advances, the synthesis of novel 3,4-dihydro-2 H -1,3-benzoxazines and the search for more efficient routes for drug discovery and medicinal chemistry are still highly desirable.…”