biotin
P. N. Confalone, J. Am. Chem. Soc. 1980, 102, 1954.
Nitrile Oxides: Applications in Total Synthesis
Me N O Cl N C O Et3N, toluene, 80 ° C Me N O
NO2
Zn, AcOH, (66%) 25 ° 4 h C,
O
Me OH
OTBDPS
vinblastine T. Fukuyama and co-workers, J. Am. Chem. Soc. 1999, 121, 3791 For a review, see Classics in Total Synthesis II, Chapter 18
H
CO2Me
N O 48 kcal
OH
J. Tufariello, Acc. Chem. Res. 1979, 12, 396.
Nitrones: Applications in Total Synthesis
CO2Me N O + OH Nitrone 1,3-dipolar cycloaddition
N O
CO2Me CO2Me Nitrone 1,3-dipolar cycloaddition N O
mCPBA N O H H O O O
CO2Me
N DBU = N Cl
Oxidative ring opening
N O MeO2C
CO2Me 1. MsCl, py 2. DBU MeO2C
CO2Me N O OH CO2Me Nitrone 1,3-dipolar cycloaddition [protection step] N O OH