Scheme 5.
Diastereoselective Propargylation of Aldehyde 25.a
aReagents and Conditions: a) DIBAL, CH2Cl2, −78 °C, 96%; b) TPAP, NMO, 4Å MS, CH2Cl2, 99%; c) SnCl4, CH2Cl2, −78 °C d) Propargyl bromide, Mg0, HgCl2, Et2O, −20 °C, 96%, dr = 84:16.
Diastereoselective Propargylation of Aldehyde 25.a
aReagents and Conditions: a) DIBAL, CH2Cl2, −78 °C, 96%; b) TPAP, NMO, 4Å MS, CH2Cl2, 99%; c) SnCl4, CH2Cl2, −78 °C d) Propargyl bromide, Mg0, HgCl2, Et2O, −20 °C, 96%, dr = 84:16.