1: DIBAL-H / tetrahydrofuran / -78 °C 2: quinolinium camphorsulfonate / toluene / 80 °C 3: 82 percent / Et3Al / toluene 4: 1.) NaH 5: 1.) n-Bu3SnH, AIBN, 2.) Mg / 1.) benzene, 80 deg C, 1 h, 2.) MeOH, 24 h, room t. View Scheme

1: DIBAL-H / tetrahydrofuran / -78 °C 2: quinolinium camphorsulfonate / toluene / 80 °C 3: 82 percent / Et3Al / toluene 4: 1.) NaH 5: 1.) n-Bu3SnH, AIBN, 2.) Mg / 1.) benzene, 80 deg C, 1 h, 2.) MeOH, 24 h, room t. 6: TFA View Scheme