Carbene-Catalyzed Formal [3+3] Cycloaddition Reaction for Access to Substituted 2-Phenylbenzothiazoles
作者:Zhibin Ni、Chengli Mou、Xun Zhu、Puying Qi、Song Yang、Yonggui Robin Chi、Zhichao Jin
DOI:10.1002/ejoc.201901773
日期:2020.1.31
carbene‐catalyzed oxidative cycloadditionreaction is developed for efficient access to multi‐functionalized 2‐phenylbenzothiazoles. A broad scope of heavily substituted arenes bearing 2‐benzothiazole groups have been prepared in good to excellent yields. The remote C(sp2)–H bond in the substituted arene products can be regioselectively activated by Pd catalysts with the direction of the 2‐benzothiazole groups
Aerobic Oxidation/Annulation Cascades through Synergistic Catalysis of RuCl<sub>3</sub>
and N-Heterocyclic Carbenes
作者:Qian Wang、Jiean Chen、Yong Huang
DOI:10.1002/chem.201803254
日期:2018.9.3
Cooperative catalysis combining a transition metal with an N‐heterocyclic carbene is challenging due to strong binding of NHCstowards late transition metals. We report the first example of synergistic catalysis by a chiral NHC and a coordinatively unsaturated ruthenium compound. RuCl3 was found to mediate efficient aerobic oxidation of homoenolates generated from enals and the N‐heterocyclic carbene
A direct method for the synthesis of β,β-disubstituted-α,β-unsaturated aldehydes via Heck reaction of aryl halides with crotonaldehyde and related substrates has been developed. The reaction provides rapid access to products usually prepared via multistep sequences. The power of the method in combination with an organocatalytic transfer hydrogenation is illustrated with a short asymmetric synthesis of (S)-Florhydral®.
N-Heterocyclic carbene-catalyzed [4+2] annulation of β-methyl enals and cyclic trifluoromethyl ketimines for the asymmetric synthesis of dihydroquinazolinone derivatives
The enantioselective oxidative N-heterocyclic carbene-catalyzed [4+2] annulation reaction of β-methyl enals and cyclic trifluoromethyl ketimines has been developed. A series of biologically interesting dihydroquinazolinone derivatives bearing a trifluoromethyl group and a tetrasubstituted stereocenter are efficiently prepared with very good yields and excellent stereoselectivities.
Carbene-Catalyzed [4 + 2] Cycloadditions of Vinyl Enolate and (in Situ Generated) Imines for Enantioselective Synthesis of Quaternary α-Amino Phosphonates
作者:Jun Sun、Chengli Mou、Zhongyao Wang、Fangcheng He、Jian Wu、Yonggui Robin Chi
DOI:10.1021/acs.orglett.8b02707
日期:2018.9.21
A carbene-catalyzed enantioselectiveaddition of enals to five-membered cyclicimines is developed. The reaction gives chiral quaternary α-amino phosphonates bearing tetrasubstituted carbon centers with excellent enantioselectivities. The imine substrates can be generated in situ from the corresponding amines under an oxidative condition that is compatible with the carbene catalysis. Thus, a one-pot