Domain: Organic synthesis / HRMS

A solution of sodium bicarbonate (10.0 equiv.) in water and a solution containing potassium iodide (KI, 6.00 equiv.) and iodine (2.00 equiv.) in water were added to a solution of 2-(((1S,4R,5R)-5-(((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-4-hydroxycyclopent-2-en-1-yl)acetic acid (1.00 equiv.) in tetrahydrofuran (THF) at room temperature. The reaction mixture was stirred for 24 h in the dark to yield compound A. To a solution of compound A (1.00 equiv.) in benzene, tributyltin hydride (3.0 equiv.) and azobisisobutyronitrile (AIBN, 0.10 equiv.) were added. The mixture was stirred at 80 °C for 1 h, affording compound B. A solution of diisobutylaluminum hydride (DIBAL-H, 2.2 equiv.) was then added dropwise to a solution of compound B (1.00 equiv.) in dichloromethane at –78 °C. After stirring for 1 h, the reaction afforded compound C.
 What is the sodium adduct mass of compound C as determined by high-resolution mass spectrometry (HRMS)?

Grading rubric:
criterion: Identifies Step 1 (iodine/KI/sodium bicarbonate) as an iodolactonization.
weight: 10
criterion: States the full IUPAC name of compound A as (3aR,4R,5S,6R,6aR)-4-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-5-hydroxy-6-iodohexahydro-2H-cyclopenta[b]furan-2-one.
weight: 10
criterion: Identifies Step 2 (tributyltin hydride/AIBN) as a radical deiodination.
weight: 10
criterion: Correctly states the IUPAC name of compound B as (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-5-hydroxyhexahydro-2H-cyclopenta[b]furan-2-one.
weight: 10
criterion: Identifies Step 3 (DIBAL-H, −78 °C) as a reduction of the lactone to a diol.
weight: 10
criterion: Correctly states the IUPAC name of compound C as (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)hexahydro-2H-cyclopenta[b]furan-2,5-diol.
weight: 20
criterion: Correctly determines the molecular formula of compound C as C17H20F2O4.
weight: 10
criterion: Correctly calculates the [M + Na]+ sodium adduct mass of compound C as 349.1222.
weight: 20

Answer:
m/z 349.1222 for [M+Na]+