Phosphoric acid derivatives nitroalkenes

This phosphoric acid derived from (i )-BINOL was also applied by Akiyama et al. as an organocatalyst to promote the highly enantioselective Friedel-Crafts alkylation of indoles with nitroalkenes, generating the corresponding Friedel-Crafts adducts with high yields and excellent enantioselectivities of up to 94% ee for a broad range of substrates in the presence of 3-A molecular sieves (Scheme 10.2). ... 

Soon afterward, various types of carbon [40-44], oxygen [45], and phosphorous [46] Michael donors were successfully employed in the thiourea-catalyzed addition to nitroalkenes. In the presence of the bifunctional epi-9-amino-9-deoxy cinchonine-based thiourea catalyst 79a, the 5-aryl-l,3-dioxolan-4-ones 138 bearing an acidic a-proton derived from mandelic acid derivatives and hexafluoroacetone were identified by Dixon and coworkers as effective pronucleophiles in diastereo- and enantioselective Michael addition reactions to nitrostyrenes 124 [40]. While the diastereoselectivity obtained exceeded 98%, the enantiomeric excess recorded... 

In 2009, You and co-workers developed a chiral phosphoric acid-catalyzed AFC reaction of nitroalkenes with 4,7-dihydroindoles. With slow addition of nitroalkene by syringe pump, the reaction proceeded to completion in 2 hours with only 0.5 mol% catalyst. The corresponding adducts were obtained in excellent yields (93-98%) with up to 97% ee. 2-Substituted indole derivatives were obtained by oxidation of AFC adducts with 2 equivalents of j3-benzoquinone without losing any ee value. You and co-workers... 

Acocella et al. reported that, in tire presence of a phosphoric acid, rac-22b derived from racemic l,l -bi-2-naphthol (BINOL), the reaction of 2-silyloxyfuran 109b with nitroalkene 118 gave the VMM adduct 119 as a mixture of syn /anti-isomers in 82% yield (Scheme 50) [85]. 

A one-pot, three component 1,3-dipolar cycloaddition reaction of aldehydes (289), a-aminomalonate (290), and nitroalkenes (291) has been developed through 3,3 anthiyl substituted hinaphthol derived chiral phosphoric acids (292) (Scheme 78). ... 

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