Intramolecular [2 + 2] cycloadditions of ketene iminium salts to carbon-carbon double bonds. William T. Brady, Yun Seng F. Giang, Lingling Weng, and ; Mohammad M. Dad

2014年4月9日 · Electrocyclizations for ketene-iminium salts were shown to be highly exergonic and have much smaller barriers to activation. Aromatic amines are very important structural motifs and building blocks which have attracted considerable attention.

Ketene-based aliphatic polyketones obtained by cationic copolymerization of dimethylketene (DMK) with diethylketene (DEK) or diphenylketene (DPK): synthesis, characterization and reactivity ratio estimation.

2014年5月1日 · We report here the synthesis of 9 GR-24 analogues via a [2+2] intramolecular cycloaddition of ketene-iminium salts and a summary of their activity for the germination of Orobanche cumana (broomrape) seeds.

2012年8月22日 · An intramolecular [2+2] cycloaddition of ketenes and ketene-iminium was developed for the preparation of GR-24, a synthetic analogue of the family of strigolactone plant hormones. Excellent levels of regioselectivity and of chiral induction were obtained using a bulky chiral amine for the formation of the cyclobutanone and a subsequent ...

2005年2月18日 · An iminium salt was easily prepared using the oxidation of amino ketene silyl acetal with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and the subsequent nucleophilic addition to this iminium species proceeded efficiently to afford α-amino esters in good yields.

An intramolecular 6p/10p-electrocyclization from ketene-iminium salts was developed for the preparation of naphthylamines. Various substituents on the nitrogen, on the aromatic ring, and on the olefin were studied.

While iminium salts generated by the oxidation of amino ketene silyl acetals show intriguing reactivities to give useful g-oxo-a-amino esters via reactions with silyl enol ethers in good yields, new iminium salts are

2019年7月31日 · Herein, we describe a very straightforward and metal free method for the synthesis of benzazepinones through an intramolecular cyclization. This involves an ortho‐vinyl‐anilino‐amide as starting material which is converted to a keteniminium intermediate that spontaneously cyclize to form a 7‐membered ring iminium. Under slightly basic ...

2003年12月1日 · Iminium salts generated by the oxidation of amino ketene silyl acetals underwent a facile Mannich reaction with another ketene silyl acetal to give the aspartic acid derivatives 35 in good yields. The diastereoselectivities were controlled to some extent by using an appropriate isomer of the ketene