Question

Hi

I have to do an mechanism  and tell witch reaction type it is (SN1 or SN2?)

I had to prepared Methyl 2,3-di-O-benzoyl-4,6-O-benzyliden-α-D-glucopyranosid from methyl α-D-glucopyranosid.

I have tried to make the mechanisme, Can you see and it is correct? It is down below.

4.1 SIMPLE PROTECTION OF MONOSACCHARIDES PH HOEKOMe HOOH O SOME HOOH Methyl 4,6-0-benzylidene-a-D-glucopyranoside: Methyl a-D-glucopyranoside (3.00 g, 15.5 mmol) is dissolved in dry acetonitrile (150 ml) in an oven-dried 250-ml round-bottomed flask, which immediately is fitted with a rubber septum. Then camphorsulphonic acid (50 mg) followed by benzaldehyde dimethylacetal (4.5 ml, 29.9 mmol) are added (by quickly removing/replacing the septum). The resulting mixture is stirred at room temperature for 2 h. Then Et3N (1.5 mL) is added, and stirring is continued for 15 min. The reaction mixture is concentrated in vacuo until the product starts precipitating from the solution. Upon cooling the product is filtered off as a white solid, which is washed with pentane (ca. 75 ml) on a Büchner funnel and then further dried (in weighed 100-ml round-bottomed flask) on the freeze- dryer for 15 min. The crude product (3.96 g, 91%) is recrystallised from EtOH (ca. 20-40 ml) to give the pure product (2.25 g, 55%) upon drying on the freeze-dryer for 30 min. TLC (heptane-acetone 1:1) of product: Rf 0.40 (plate is developed with 5% H2SO4 in methanol followed by heating).

Is this correct?