Chiral multifunctional phosphine

Scheme 13.22 Asymmetric aza MBH reaction catalyzed by other chiral multifunctional phosphine catalysts.

In the course of developing an easy access to chiral y-butenolides, Shi et al. have established an efficient multifunctional chiral binaphthyl phosphine-catalysed allylic substitution of Morita-Baylis-Hillman acetate with 2-tri-methylsiloxy furan. The regjospecific allylic substitution occurred to provide the xyra-y-butenolide in good to excellent yield, high regjoselectivity and excellent enantioselectivity by using water as an additive. The scope of this reaction could be successfully extended to a variety of Morita Baylis Hillman acetates, as shown in Scheme 5.10. 

Deng, H.-R, Wang, D., Wei, Y., Shi, M. (2012). Chiral multifunctional thiourea-phosphine catalyzed asymmetric [3 -I- 2] aimulation of Morita-Baylis-HUlman carbonates with maleimides. Beilstein Journal of Organic Chemistry, 8,1098-1104. 

The asymmetric allylic substitution reaction of Morita-Baylis-Hillman carbonates (226) with diphenyl phosphite in the presence of chiral multifunctional thiourea-phosphine catalyst (228) provided allylic phosphites (227) in high yields and with excellent enantioselectivities (Scheme 76). 

Aza-MBH reaction between acrylonitrile (30) and imines (29) has been achieved with 98% ee using chiral phebim/Pd(II) complexes (32) to form a-methylene- -aminonitriles (31). Aza-MBH reactions of ArCH=NTs with electronically and 0 sterically deactivated Michael acceptors can be achieved by the use of electron-rich phosphanes (PArg) and pyridines (33) as catalysts (Scheme 21) Nucleophilic and steric influences, respectively, are exerted by new multifunctional chiral phosphines and BINOL derivatives used to cocatalyse aza-MBH reactions of 5,5-disubstituted cyclopent-2-enone and RCH=NTs in THF, with 99% yield and 85% ee ... 

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