Hydroxy aldehydes from epoxides

All the elements constituting the Julia reaction were known well before the assembling of this sequence by Julia and his group. In 1937, the first coupling between an aldehyde and an a-sulfonyl carbanion was performed [5] (reaction 3.1 Scheme 3.3). In reaction 3.2, a subsequent dehydration of the alcohol 12 under acidic conditions leads to the corresponding vinyl sulfone 13 [6]. An alternative method had been developed earlier by Culvenor et al. to synthesize jS-hydroxy sulfones from epoxides rather than aldehydes [7] (reaction 3.3). 

P-Hydroxy selenides are conveniently prepared from epoxides by treatment with sodium phenylse-lenide (Scheme 32) and by the addition of benzeneselenenic acid and its derivatives to alkenes (Scheme 33), - -" although in some cases these reactions are not regioselective. Useful phenylseleno -etherification and -lactonization reactions have been developed which can be regioselective (equation 42 and Schemes 34 and 35). -" " Selenide- and selenoxide-stabilized carbanions have been used in addition reactions with aldehydes and ketones, - and the reduction of a-seleno ketones also provides a route to P-hydroxy selenides. ... 

Lithiated 1,3-dithianes react readily with epoxides to give thio-acetals of 13-hydroxy aldehydes or ketones. Addition of carbonyl electrophiles to 2-lithio-1,3-dithiane is efficient and provides a method for preparing a-hydroxy carbonyl compounds. For example, the ketone 120 can be converted into the hydroxy aldehyde 122 via the alcohol 121 (1.108). The dithiane approaches the ketone from the less-hindered convex face of the fused ring system. 

Several homogeneous metal catalysts related to hydroformylation based on Co, Rh, Pt, Pd, or Ir are able to open epoxides (oxiranes) [1]. In the 1980s, Milstein and Bergman [2] could intercept some metal alkyl enolates derived from this reaction. Such complexes can undergo CO insertion to give metal-acyl complexes. By final hydrogenolysis, P-hydroxy aldehydes result. 

Reaction of the carbanion of chloromethyl phenyl sulphoxide 409 with carbonyl compounds yields the corresponding 0-hydroxy adducts 410 in 68-79% yield. Each of these compounds appears to be a single isomer (equation 242). Treatment of adducts 410 with dilute potassium hydroxide in methanol at room temperature gives the epoxy sulphoxides 411 (equation 243). The ease of this intramolecular displacement of chloride ion contrasts with a great difficulty in displacing chloride ion from chloromethyl phenyl sulphoxide by external nucleophiles . When chloromethyl methyl sulphoxide 412 is reacted with unsymmetrical ketones in the presence of potassium tcrt-butoxide in tert-butanol oxiranes are directly formed as a mixture of diastereoisomers (equation 244). a-Sulphinyl epoxides 413 rearrange to a-sulphinyl aldehydes 414 or ketones, which can be transformed by elimination of sulphenic acid into a, 8-unsaturated aldehydes or ketones (equation 245). The lithium salts (410a) of a-chloro-/ -hydroxyalkyl... 

---