One-pot access to tetrahydrobenzo[<i>c</i>]carbazoles from simple ketones by using O<sub>2</sub> as an oxidant
作者:Shuvendu Saha、Modhu Sudan Maji
DOI:10.1039/c9ob02751c
日期:——
diversely functionalized carbazole frameworks starting from protecting group free 2-alkenyl indoles. The employment of easily available unactivated ketones as annulating partners, mostly unexplored for the synthesis of carbazoles, is the major highlight of this protocol. This protocol is step- and atom-economical, uses molecular oxygen as the green oxidant, and gives water as the only by-product and is amenable
Brønsted Acid Catalyzed One-Pot Benzannulation of 2-Alkenylindoles under Aerial Oxidation: A Route to Carbazoles and Indolo[2,3-<i>a</i>]carbazole Alkaloids
作者:Shuvendu Saha、Ankush Banerjee、Modhu Sudan Maji
DOI:10.1021/acs.orglett.8b03063
日期:2018.11.2
A one-pot, protecting-group-free benzannulation of 2-alkenylindoles with readily available 1,3-dicarbonyls is demonstrated to construct structurally diverse carbazoles. The use of a cheap Brønsted acid catalyst and air as the sole oxidant exemplifies the economic viability of this protocol. The execution of four different reactions successively to generate the medicinally important indolocarbazole
Homo‐ and cross‐[4+2] cycloadditions of 2‐alkenylindoles, catalyzed by cationic halogen‐bonddonors, were developed. Under mild reaction conditions, 3‐indolyl‐substituted tetrahydrocarbazole derivatives were obtained in good to excellent yields. Experimental and quantum calculation studies revealed that the electrophilic activation of 2‐alkenylindoles was achieved by C−I⋅⋅⋅π halogen bonds.
[EN] 2-VINYL INDOLES, PYRIDO AND AZEPINO INDOLE DERIVATIVES, 2-ALKYNYL INDOLES, 2-ALKYNYL BENZO[b]FURANS, THEIR PRECURSORS AND NOVEL PROCESSES FOR THE PREPARATION THEREOF<br/>[FR] 2-VINYLINDOLES, DÉRIVÉS PYRIDO ET AZÉPINOINDOLE, 2-ALCYNYLINDOLES, 2-ALCYNYLBENZO[b]FURANNES, LEURS PRÉCURSEURS ET LEURS NOUVEAUX PROCÉDÉS DE PRÉPARATION
申请人:LAUTENS MARK
公开号:WO2007134421A1
公开(公告)日:2007-11-29
[EN] The present invention relates to the preparation of 2-vinyl indoles from ortho-gem-dibromovinylaniline compounds and alkene reagents using a palladium pre-catalyst, a base, and, in some instances, a ligand or additive. The present invention also relates to the preparation of pyrido and azepino derivatives via a palladium-catalyzed tandem intramolecular Buchwald-Hartwig amination and Heck coupling reaction of appropriately functionalized ortho-gem-dibromovinylanilines. The present invention also relates to the preparation of 2-alkynyl indoles from ortho-gem-dibromovinylaniline compounds and alkyne reagents using a palladium pre-catalyst, a copper pre-catalyst, a base, and a ligand. Novel processes for the preparation of benzo[b]furan compounds are also disclosed, wherein the 2-alkynyl benzo[b]furans are prepared from ortho-gem-dibromovinylphenol compounds and alkyne reagents using a palladium pre-catalyst, a copper pre-catalyst, a base, and a ligand. [FR] La présente invention concerne la préparation de 2-vinylindoles à partir de composés ortho-gem-dibromovinylanilineet de réactifs alcène, préparation dans laquelle on utilise un pré-catalyseur à base de palladium, une base, et, parfois, un ligand ou un additif. La présente invention concerne également la préparation de dérivés pyrido et azépino par l'intermédiaire d'une réaction intramoléculaire tandem catalysée par le palladium d'amination de Buchwald-Hartwig et de couplage de Heck d'ortho-gem-dibromovinylanilines convenablement fonctionnalisés. La présente invention concerne également la préparation de 2-alcynylindoles à partir de composés ortho-gem-dibromovinylaniline et de réactifs alcyne effectuée en utilisant un pré-catalyseur à base de palladium, un pré-catalyseur à base de cuivre, une base et un ligand. La présente invention concerne également des nouveaux procédés de préparation de composés benzo[b]furanne, où les 2-alcynylbenzo[b]furannes sont préparés à partir de composés ortho-gem-dibromovinylphénol et de réactifs alcyne en utilisant un pré-catalyseur à base de palladium, un pré-catalyseur à base de cuivre, une base et un ligand.