Asymmetric carbonyl-ene and Friedel–Crafts reactions catalysed by Lewis acid platinum group metal complexes of the enantiopure atropisomeric biaryl-like diphosphine (S)-Me2-CATPHOS: a comparison with BINAP

Lewis acid platinum and palladium complexes of (S)-Me2-CATPHOS catalyse the carbonyl-ene reaction between allylbenzene derivatives and ethyl trifluoropyruvate to give the expected α-hydroxy esters with ee’s up to 97%, while the corresponding reaction involving 2-allylfuran and thiophene was exclusively selective for Friedel–Crafts-type reactivity and gave the corresponding 2-hydroxy-trifluoromethyl ethyl esters in good yield and moderate to good enantioselectivity.

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(R)-Ethyl 2-hydroxy-4-phenyl-2-trifluoromethylpent-4-enoateC14H15F3O3Ee = 65%[α]D = +26.1 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 4-(4-chlorophenyl)-2-hydroxy-2-trifluoromethylpent-4-enoateC14H15ClF3O3Ee = 38%[α]D = +14.7 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 4-(o-tolyl)-2-hydroxy-2-trifluoromethylpent-4-enoateC15H17F3O3Ee = 82%[α]D = +43.0 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl E-2-(trifluoromethyl)-2-hydroxy-5-p-tolylpent-4-enoateC15H17F3O4Ee = 70%[α]D = +34.2 (c 1.22, CH2Cl2)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl E-2-(trifluoromethyl)-2-hydroxy-5-(2-methylphenyl)pent-4-enoateC15H17F3O3Ee = 67%[α]D = +21.4 (c 1.0, CH2Cl2)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl E-2-(trifluoromethyl)-2-hydroxy-5-(3,5-dimethylphenyl)pent-4-enoateC16H19F3O3Ee = 94%[α]D = +43.1 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl E-2-(trifluoromethyl)-2-hydroxy-5-(4-chlorophenyl)pent-4-enoateC14H14F3ClO3Ee = 99%[α]D = +33.5 (c 1.0, CH2Cl2)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 2-(5-allylfuran-2-yl)-3,3,3-trifluoro-2-hydroxypropanoateC12H13F3O4Ee = 67%[α]D = −16.1 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 2-(5-allylthiophen-2-yl)-3,3,3-trifluoro-2-hydroxypropanoateC12H13F3O3SEe = 63%[α]D = −16.0 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 3,3,3-trifluoro-2-(furan-2-yl)-2-hydroxypropanoateC9H9F3O4Ee = 67%[α]D = −15.1 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 3,3,3-trifluoro-2-hydroxy-2-(thiophen-2-yl) propanoateC9H9F3O3SEe = 79%[α]D = −13.7 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 3,3,3-trifluoro-2-hydroxy-2-(5-methylfuran-2-yl)propanoateC10H11F3O3SEe = 80%[α]D = −11.8 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis

(R)-Ethyl 3,3,3-trifluoro-2-hydroxy-2-(5-methylthiophen-2-yl)propanoateC12H13F3O3SEe = 67%[α]D = −6.1 (c 1.0, CHCl3)Absolute configuration: (R)Source of chirality: asymmetric catalysis