Nickel/Bis(oxazoline)-Catalyzed Asymmetric Negishi Arylations of Racemic Secondary Benzylic Electrophiles to Generate Enantioenriched 1,1-Diarylalkanes
作者:Hien-Quang Do、E. R. R. Chandrashekar、Gregory C. Fu
DOI:10.1021/ja408561b
日期:2013.11.6
A tertiary stereogenic center that bears two different aryl substituents is found in a variety of bioactive compounds, including medicines such as Zoloft and Detrol. We have developed an efficient method for the synthesis of enantioenriched 1,1-diarylalkanes from readily available racemic benzylic alcohols. Formation of a benzylic mesylate (which is not isolated), followed by treatment with an arylzinc reagent, LiI, and a chiral nickel/bis(oxazoline) catalyst, furnishes the Negishi cross-coupling product in high ee and good yield. A wide array of functional groups (e.g., an aryl iodide, a thiophene, and an N-Boc-indole) are compatible with the mild reaction conditions. This method has been applied to a gram-scale synthesis of a precursor to Zoloft.
Preparation of optically active 2-furylcarbinols by kinetic resolution using the Sharpless reagent and their application in organic synthesis
作者:Masato Kusakabe、Yasunori Kitano、Yuichi Kobayashi、Fumie Sato
DOI:10.1021/jo00270a015
日期:1989.4
KUSAKABE, MASATO;KITANO, YASUNORI;KOBAYASHI, YUICHI;SATO, FUMIE, J. ORG. CHEM., 54,(1989) N, C. 2085-2091
diastereoselective synthesis of 4-vinyl oxazolines syn-2 was developed based on an acid-catalyzed cyclization of bistrichloroacetimidates (E)-1. The reaction likely involves an allyl carbenium ion intermediate in which the adjacent stereocenter directs the stereoselectivity for C–N bond formation. Oxazolines syn-2 were transformed to C-quaternary threoninol, threoninal, and threoninederivatives which can be
Addition/Oxidative Rearrangement of 3-Furfurals and 3-Furyl Imines: New Approaches to Substituted Furans and Pyrroles
作者:Ann Rowley Kelly、Michael H. Kerrigan、Patrick J. Walsh
DOI:10.1021/ja710988q
日期:2008.3.1
oxidative rearrangement proceeds through an unsaturated 1,4-dialdehyde intermediate. The alcohol then cyclizes onto an aldehyde, resulting in the elimination of water and rearomatization. On the basis of this proposed mechanism, we found that 3-furyl imines undergo the addition of organometallic reagents to provide furyl sulfonamides. Under the oxidative rearrangement conditions, 2-substituted 3-formyl