6738-27-8Relevant articles and documents
Isothiourea-catalyzed enantioselective α-alkylation of esters via 1,6-conjugate addition to para-quinone methides
Arokianathar, Jude N.,Greenhalgh, Mark D.,Hartley, Will C.,McLaughlin, Calum,Ng, Sean,Slawin, Alexandra M. Z.,Smith, Andrew D.,Stead, Darren
supporting information, (2021/11/01)
The isothiourea-catalyzed enantioselective 1,6-conjugate addition of para-nitrophenyl esters to 2,6-disubstituted para-quinone methides is reported. para-Nitrophenoxide, generated in situ from initial N-acylation of the isothiourea by the para-nitrophenyl ester, is proposed to facilitate catalyst turnover in this transformation. A range of para-nitrophenyl ester products can be isolated, or derivatized in situ by addition of benzylamine to give amides at up to 99% yield. Although low diastereocontrol is observed, the diastereoisomeric ester products are separable and formed with high enantiocontrol (up to 94:6 er).
Organocatalyzed asymmetric 1,6-conjugate addition of para-quinone methides with dicyanoolefins
Li, Xuanyi,Xu, Xiuyan,Wei, Weiwei,Lin, Aijun,Yao, Hequan
supporting information, p. 428 - 431 (2016/02/19)
A chiral thiourea catalyzed asymmetric 1,6-conjugate addition of para-quinone methides with dicyanoolefins has been developed. The reaction provided an efficient approach to the synthesis of chiral diarylmethine skeletons in good yields (up to 99% yield) with high diastereo- and enantioselectivity (>20:1 dr and up to 99.5:0.5 er), also on a gram scale. The preliminary mechanistic study showed that the remote stereocontrol was achieved through intermolecular hydrogen-bond interaction between the chiral thiourea catalyst and the para-quinone methides directly for the first time.
Synthesis of spiro[2.5]octa-4,7-dien-6-one with consecutive quaternary centers via 1,6-conjugate addition induced dearomatization of para-quinone methides
Gai, Kuo,Fang, Xinxin,Li, Xuanyi,Xu, Jinyi,Wu, Xiaoming,Lin, Aijun,Yao, Hequan
supporting information, p. 15831 - 15834 (2015/11/10)
An efficient one-pot approach for the synthesis of spiro[2.5]octa-4,7-dien-6-ones by employing para-quinone methides has been developed. The reaction proceeded smoothly in high yields under mild conditions without the use of metals. Moreover, all products obtained herein contained two or three consecutive quaternary centers.