Highly Enantioselective Nickel-Catalyzed Oxa-[3+3]-annulation of Phenols with Benzylidene Pyruvates for Chiral Chromans
作者:Hai Ren、Xiang-Yang Song、Sunewang R. Wang、Lijia Wang、Yong Tang
DOI:10.1021/acs.orglett.8b01442
日期:2018.7.6
Nickel-catalyzed asymmetric annulation of oxygenated phenols and previously challenging 3-aminophenols with β,γ-unsaturated α-ketoesters is described, leading to rapid access to a variety of oxygenated and 7-aminated chromans in excellent yields with excellent diastereoselectivities and enantioselectivities under mild conditions. This method was readily scaled-up to gram scale and applied for a concise
Stereodivergent Synthesis of Enantioenriched 2,3-Disubstituted Dihydrobenzofurans via a One-Pot C–H Functionalization/Oxa-Michael Addition Cascade
作者:Dong-Xing Zhu、Jian-Guo Liu、Ming-Hua Xu
DOI:10.1021/jacs.1c03498
日期:2021.6.16
A one-pot rhodium-catalyzed C–H functionalization/organocatalyzed oxa-Michael addition cascade reaction has been developed. This methodology enables the stereodivergent synthesis of diverse 2,3-disubstituted dihydrobenzofurans with broad functional group compatibility in good yields with high levels of stereoselectivity under exceptionally mild conditions. The full complement of stereoisomers of chiral
A Phosphine-Mediated Dearomative Skeletal Rearrangement of Dianiline Squaraine Dyes
作者:Emily P. Bacher、Kevin J. Koh、Antonio J. Lepore、Allen G. Oliver、Olaf Wiest、Brandon L. Ashfeld
DOI:10.1021/acs.orglett.1c00248
日期:2021.4.16
A phosphorus(III)-mediated dearomatization of ortho-substituted dianiline squaraine dyes results in an unusual skeletalrearrangement to provide exotic, highly conjugated benzofuranone and oxindole scaffolds bearing a C3 side chain comprised of a linear conflagration of an enol, a phosphorus ylide, and 2,4-disubstituted aniline. Employing experimental and computational analysis, a mechanistic evaluation
Diastereoselective Intramolecular Aldol-Type Trapping of Zwitterionic Intermediates by Ketones for the Synthesis of Spiro[chroman-4,3′-oxindole] Derivatives
作者:Shikun Jia、Yubing Lei、Longlong Song、A. Gopi Krishna Reddy、Dong Xing、Wenhao Hu
DOI:10.1002/adsc.201600998
日期:2017.1.4
A simple, mild and efficient rhodium‐catalyzed aromatic C–H functionalization of α‐phenoxy ketones by 3‐diazooxindoles for the synthesis of the spiro[chroman‐4,3′‐oxindole] ring system is described. A series of functionalized spiro[chroman‐4,3′‐oxindole] derivatives bearing two adjacent quaternary carbon centers have been attained in a highly diastereoselective manner with very good yields. Control
The present invention provides novel, water-soluble, red-emitting fluorescent rhodamine dyes and red-emitting fluorescent energy-transfer dye pairs, as well as labeled conjugates comprising the same and methods for their use. The dyes, energy-transfer dye pairs and labeled conjugates are useful in a variety of aqueous-based applications, particularly in assays involving staining of cells, protein binding, and/or analysis of nucleic acids, such as hybridization assays and nucleic acid sequencing.