Catalytic, Enantioselective, Intramolecular Sulfenoamination of Alkenes with Anilines

Abstract

A method for the catalytic, enantioselective, intramolecular sulfenoamination of alkenes with aniline nucleophiles has been developed. The method employs a chiral, Lewis basic selenophosphoramide catalyst and a Brønsted acid co-catalyst to promote stereocontrolled C–N and C–S bond formation by activation of an achiral sulfenylating agent. Benzoannulated nitrogen-containing heterocycles such as indolines, tetrahydroquinolines, and tetrahydrobenzazepines were prepared with high to excellent enantioselectivities. The impact of tether length and electron density of both the nucleophile and olefin on the reactivity, site selectivity, and enantioselectivity were investigated and interpreted in terms of substrate-dependent stereodetermining thiiranium ion formation or capture.

Structural, Mechanistic, Spectroscopic, and Preparative Studies on the Lewis Base Catalyzed, Enantioselective Sulfenofunctionalization of Alkenes

“…[26] [27] The protocol has been applied to tosyl-protected amines that can be engaged in sulfenoamination reactions yielding enantioenriched nitrogen heterocycles (lower, Scheme 5). [28] More recently, the process has been extended to include sulfenocyclization reactions involving both phenols [29] and anilines [30] with great success. The catalytic, enantioselective sulfenylation of ketonederived enoxysilanes has also been demonstrated (not shown).…”

Electrophilic Selenium Catalysis with Electrophilic N-F Reagents as the Oxidants

“…Asymmetric conversion plays an important role in modern synthesis owing to the realization of the different properties of enantiomer in biology. Over the past years, several ingenious organoselenium catalyzed enantioselective reactions have been developed, but most successful cases focused on the utilization of selenium in Lewis-base catalysis [ 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 ]. To date, efficient asymmetric conversion is still rare in electrophilic selenium catalysis although considerable efforts have been devoted in this field [ 93 , 94 , 95 , 96 , 97 ].…”

Enantio‐ and Diastereoselective, Lewis Base Catalyzed, Cascade Sulfenoacetalization of Alkenyl Aldehydes

“…Combination of as uitable electrophilic sulfur source with ac hiral selenophosphoramide catalyst results in ac ationic donor-acceptor complex with increased electrophilic character on sulfur.T he active catalytic species then transfers the sulfenium ion to the olefin to generate an enantiomerically enriched thiiranium ion, followed by ad iastereospecific capture with as uitable nucleophilic partner (Scheme 1A). [12] Thec urrent scope of nucleophiles includes oxygen, [13] nitrogen, [14] and carbon [15] moieties,a cting in both an intra-and intermolecular fashion. This method also provides access to aw ide variety of enantioenriched carboand heterocycles,i ncluding complex polycyclic natural products.…”