Synthesis of Biaryl Phosphorus Compounds

As shown in Sections 9.4.1 and 9.4.2, electron-deficient and coordinating alkynyl carbonyl compounds showed high reactivity in cationic rhodium(I)/biaryl bispho-sphine complex-catalyzed enantioselective [2- -2-1-2] cycloaddition. Therefore, Tanaka et al. investigated the use of alkynylphosphonates or alkynylphosphine oxides instead of alkynyl carbonyl compounds for the practical synthesis of axially chiral biaryl phosphorus compounds. The enantioselective [2- -2-1-2] cycloadditon 

73 with 1,6-diynes 72 proceeded at room temperature in the presence of the cationic rhodium(I)/Hg-BINAP catalyst to give axially chiral biaryl phosphorus compounds 

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