Calcium VAPOL

Calcium VAPOL (2,2 -diphenyl-(4-biphenanthrol)) phosphate (150) has been reported as an efficient catalyst for the enantioselective Michael addition of 3-aryloxindoles to CH2=CHCOMe (<95% ee) and for chlorination of 3-substituted oxindoles with A-chlorosuccinimide (<99% ee). ... 

Antilla et al. reported chiral calcium VAPOL phosphate-mediated asymmetric 1,4-addition reactions of 3-substituted oxindoles (Table 13) [59] for reviews of asymmetric reactions of oxindole, see [60-63]. It was showed that VAPOL phosphate could be applied, and the desired products were obtained in excellent yields with high enantioselectivities. Four differently substituted oxindoles worked well in this reaction. 

Zheng W, Zhang Z, Kaplan MJ, Antilla JC. Chiral calcium VAPOL phosphate mediated asymmetric chlorination and Michael reactions of 3-substituted oxindoles. J. Am. Chem. Soc. 2011 133(10) 3339-3341. 

A 1 1 mixture of calcium and magnesium VAPOL phosphates has been shown to catalyse the ring-opening reaction of nteio-aziridines by McgSi-X, where X = SPh, SePh, SR, NCS, or N3 in moderate to high yields (53-100%) and enantioselectivities (42-96%)." A mechanism is proposed for the reactions. 

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