Enantioselective Diels–Alder Reaction of α-(Acylthio)acroleins: A New Entry to Sulfur-Containing Chiral Quaternary Carbons
作者:Akira Sakakura、Hiroki Yamada、Kazuaki Ishihara
DOI:10.1021/ol300921f
日期:2012.6.15
A catalytic and enantioselectiveDiels–Alderreaction of α-(carbamoylthio)acroleins induced by an organoammonium salt of chiral triamine is described. α-(Carbamoylthio)acroleins are designed and synthesized as new sulfur-containing dienophiles for the first time. The Diels–Alderreaction affords chiral tertiary thiol precursors with up to 91% ee.
selective dehydrohalogenation to form alpha-haloacrylate analogues. A variety of alpha-halo Michael acceptors were prepared in dimethyl sulfoxide under mild, base-free conditions, including the preparation of alpha-bromoacrolein and alpha-chloro- and bromoacrylonitriles. Synthesis of these molecules has been reported in the literature to be difficult. Among all the existing dehydrohalogenation procedures
Syntheses of Strychnine, Norfluorocurarine, Dehydrodesacetylretuline, and Valparicine Enabled by Intramolecular Cycloadditions of Zincke Aldehydes
作者:David B. C. Martin、Lucas Q. Nguyen、Christopher D. Vanderwal
DOI:10.1021/jo2020246
日期:2012.1.6
base-mediated intramolecular Diels–Alder cycloadditions of tryptamine-derived Zincke aldehydes is described. This important complexity-generating transformation provides the tetracyclic core of many indole monoterpene alkaloids in only three steps from commercially available starting materials and played a key role in short syntheses of norfluorocurarine (five steps), dehydrodesacetylretuline (six steps), valparicine
<scp>DMAP‐Catalyzed</scp>
C—N Bond Formation for Diverse Synthesis of Imidazo[1,2‐
<i>a</i>
]pyrimidine and Pyrimido[1,2‐
<i>a</i>
]benzimidazole Derivatives
作者:Le‐Le Shang、Yun Feng、Xing‐Lian Gao、Zi‐Ren Chen、Yu Xia、Wei‐Wei Jin、Chen‐Jiang Liu
DOI:10.1002/cjoc.202000214
日期:2020.12
A DMAP (2‐dimethylaminopyridine)‐catalyzed condensation reactions for the successful direct construction of pyrimido[1,2‐a]benzimidazole or imidazo[1,2‐a]pyrimidine has been developed. The method utilizes readily available α‐bromocinnamaldehydes with 2‐aminobenzimidazole or 2‐aminoimidazole as starting materials in the presence of 2‐DMAP/TBHP. In the process, two C—N bonds were successfully constructed