[snowlynch]

MOM protection can be done in many different ways? which condition is the best?
I know this paper has a mild condition and the reaction is very fast, but I can not download the paper.
 K. Fuji, S. Nakano and E. Fujita. Synthesis 276 (1975).
Who knows what the exact way this paper do may be OK too.
If who has the paper file will be perfect!!!

[craken66]

1

[Borek]

Please do not solicit copyrighted materials on this forum.

[gregbahun]

i've followed that prep. it's ok. but they use a huge excess of P2O5. this causes a fair bit of heat to come off when washing with bicarbonate. so much so that...let's just say i lost some material to charring. here's a rough recap of the procedure I followed.

0.17 mmol of alcohol, 11.5 mmol of methylal (ie, dimethoxymethane), 500 mg of P2O5, in 1 mL of CHCl3 (which was dried over P2O5). After 30 min (done by TLC), pour into ice-cooled carbonate solution. Wash out flask with same, combine,  and then extract with ether. wash with brine, dry. they got a 94 % yield.

here's another procedure if you haven't found one already.

http://www3.interscience.wiley.com/journal/60501999/abstract

quick summary: 1 eq of alcohol, 1.1 eq of P2O5, 10 eq of methylal, 100 mL of dry CHCl3. stirred RT overnight. add another 100 mL CHCl3 and then some crushed ice to mixture, then neutralized with carbonate solution. extract, wash...etc. 84 % yield