P-Iodobenzyl alcohol

A soln. of p-iodobenzyl alcohol and 2,6-lutidine in chloroform added to 2,3,4,6-tetra-O-acetyl-a-D-mannopyranosyl bromide, and stored 24hrs. at room temp. 3,4,6-tri-0-acetyl-/ -D-mannopyranose 1,2- (p-iodobenzyl orthoacetate). Y 69%. F. e. s. M. Mazurek and A. S. Perlin, Can. J. Chem. A3, 1918 (1965) with tetra-n-butylammonium bromide in spm-collidine s. R. U. Lemieux and A. R. Morgan, Gan. J. Ghem. 43, 2199. 

The lactonization of o-iodobenzyl alcohol 311 was performed in the presence of PdCl2[(P(OEt)3]2 (0.02 mol%) and triethylamine (2.2 equiv.) at 130°C and 5 atm of CO in SCCO2 (200atm) to give phthalide 312 quantitatively (Equation (28)). " In this reaction, the turnover number (TON) in SCCO2 reached 5000 after 18h, which was considerably better than that in toluene (3800). Moreovet, the reaction in SCCO2 reached 4700 TON after 6h as compared to only 1100 TON for that in toluene. 

Ikariya and co-workers reported an efficient palladium-catalyzed carbonylation of aryl halides in sc C02 (eq. 2.10) (Kayaki et al., 1999). 2-Iodobenzyl alcohol was converted to the phthalide in the presence of PdCl2L2 [L = PMe3, PPh3, MeCN, P(OEt)3, P(OPh)3, PPh(OMe)2, PPh2(OMe)] with higher rates in sc C02 than in toluene. 

---