[56161-54-7] · C12H16O4S · 4-Phenylsulfonyl-2-butanone Ethylene Acetal · (MW 256.35)
(a reagent for synthesizing various derivatives of 2-alkanones)
Alternate Name: PSB-EA.
Monoalkylation of 4-phenylsulfonyl-2-butanone ethylene acetal (1) takes place at the position a to the phenylsulfonyl group on successive treatment with n-Butyllithium and then with an alkyl halide (or tosylate). Deprotection of the acetal group and subsequent elimination of the benzenesulfinic acid moiety with a base transforms the monoalkylation product to the corresponding 3-alken-2-one (eq 1).1,3 A 2-alkanone is obtainable from the monoalkylation product by reductive desulfurization and subsequent acidic deprotection (eq 2).2-5
On treatment with n-BuLi and an acyl chloride, (1) affords an a-acylated product, which easily undergoes reductive desulfurization with Aluminum Amalgam or Sodium Amalgam. Deprotection forms an alkane-2,5-dione (eq 3).6,7
The lithio derivative of (1) reacts with a terminal epoxide to give a ring-opened product. Acidic deprotection of the product forms 6-hydroxy-2-alkanone which cyclizes to give a d-lactol (eq 4).8
3-(Phenylsulfonyl)propanal Ethylene Acetal.
Chiba University, Japan