Asymmetric Br?nsted Acid Catalyzed Substitution of Diaryl Methanols with Thiols and Alcohols for the Synthesis of Chiral Thioethers and Ethers
An enantioselective addition of thiols and alcohols to aza-ortho-quinone methides, starting from diaryl methanols, was developed. The asymmetric additions occur under mild reaction conditions in the presence of chiral phosphoric acids and furnish the corresponding adducts with excellent yields and enantioselectivities. Take two: An enantioselective addition of thiols and alcohols to aza-ortho-quinone methides, starting from diaryl methanols, has been developed. The asymmetric oxa- and sulfa-Michael additions proceed under mild reaction conditions in the presence of chiral phosphoric acids to furnish the corresponding adducts with excellent yields and enantioselectivities.
Chatupheeraphat, Adisak,Liao, Hsuan-Hung,Mader, Steffen,Sako, Makoto,Sasai, Hiroaki,Atodiresei, Iuliana,Rueping, Magnus
supporting information
p. 4803 - 4807
(2016/04/19)
Asymmetric Bronsted Acid Catalyzed Synthesis of Triarylmethanes - Construction of Communesin and Spiroindoline Scaffolds
Aza-ortho-quinone methides allow the straightforward asymmetric synthesis of natural-product-inspired indole scaffolds possessing a quaternary stereocenter. Our approach provides access to diverse communesin and spiroindoline derivatives with high enantioselectivity under mild reaction conditions. Predictable substitution patterns are found to be the key to our regiodivergent protocols. Two protocols have been developed for the regiodivergent, asymmetric Bronsted acid catalyzed addition of indoles to in situ generated aza-ortho-quinone methides. Furthermore, a new addition spirocyclization sequence leads, depending on the indole derivative, to communesin and spiroindoline cores with quaternary stereocenters.
Liao, Hsuan-Hung,Chatupheeraphat, Adisak,Hsiao, Chien-Chi,Atodiresei, Iuliana,Rueping, Magnus
supporting information
p. 15540 - 15544
(2016/01/26)
Aminohaloborane in Organic Synthesis. X. A Convenient, Economical Exclusive ortho Substitution Reaction of N-Alkyl and N-Aminoalkyl Anilines
A method for in situ generation of boron trichloride from boron trifluoride etherate and silicon tetrachloride in the presence of triethylamine, traced by boron-11 nuclear magnetic resonance (11B-NMR) spectroscopy, was successfully developed, thus elimina