Rhodium-Catalyzed Asymmetric N−H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (−)-Chaetominine
作者:Yirong Zhou、Bernhard Breit
DOI:10.1002/chem.201705059
日期:2017.12.22
An unprecedented asymmetric N−H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo‐, regio‐, and enantioselectivities with broad functional
Regioselective and enantiospecific rhodium-catalyzed allylic amination with thymine: synthesis of a new conformationally rigid nucleoside
作者:P. Andrew Evans、Kwong Wah Lai、Hai-Ren Zhang、John C. Huffman
DOI:10.1039/b513083b
日期:——
The regioselective and enantiospecific rhodium-catalyzed allylic amination of secondary allylic carbonates with N3-benzoyl thymine in conjunction with a stereoselective free radical cyclization provides a convenient method for the construction of a new conformationally rigid nucleoside.
1,2-Benzothiazines from Sulfoximines and Allyl Methyl Carbonate by Rhodium-Catalyzed Cross-Coupling and Oxidative Cyclization
作者:Jian Wen、Deo Prakash Tiwari、Carsten Bolm
DOI:10.1021/acs.orglett.7b00488
日期:2017.4.7
4-Unsubstituted 1,2-benzothiazines are prepared from sulfoximines and allyl methyl carbonate by Rh(III)-catalyzed domino allylation/oxidative cyclization. A wide range of functional groups on the sulfoximine are tolerated. A plausible mechanism is proposed, and chemical modifications of the products have been explored.
Palladium(0)-catalyzed alkylation of various allylic acetates and carbonates by potassium thioacetate allowed an easy access to allylic thioacetates in rather good yields. The reaction was regioselective with substitution at the less hindered side of the intermediate π-allyl system, and diastereoselective with net retention of configuration.
Co‐catalyzedallylic substitution reactions have received little attention, arguably because of the lack of any known advantage of Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective Co‐catalyzedallylicalkylation using an in situ catalyst activation by organophotoredox catalysis. This noble‐metal‐free catalytic system exhibits unprecedentedly high reactivities