Selective reduction of .alpha.-keto acids to .alpha.-hydroxy acids by phosphites

Reductive condensation of methyl arylglyoxylates. Direct synthesis of 2,3-bis(carbomethoxy)stilbene oxides and related systems

“…Anal. Caled for C17H13N03: C, 73.11; H, 4.69; N, 5.01. Found: C, 73.39; , 4.80; N, 4.90. cis -Epoxydiphenylsuccinic Acid (18). cis-2,3-Bis(carbomethoxy)stilbene oxide (13a) (0.30 g, 1.1 mmol) was stirred overnight in a solution of 1 N sodium methoxide in methanol to which was added water (0.2 mL) at ambient temperature.…”

“…Finally, an alternate route to the cis dibasic acid 18, and thus ultimately the cis diester 13a, was also developed involving treatment of diphenylmaleic anhydride with bromine in dimethylformamide containing lithium hydroxide which gives cis-diphenylepoxysuccinic acid (18), presumably through cyclization of an intermediate bromohydrin and accompanying hydrolysis of the anhydride.…”

“…The aliphatic and aromatic glyoxylic acids undergo selective reduction to -hydroxy acids by trialkyl phosphites. 18 Fortunately, such is not a major reaction pathway with arylglyoxylate esters, at least when hexamethylphosphorous triamide is employed as the reducing agent.…”

Reactions of N-phthalylamino acid chlorides with trialkyl phosphites

“…Interestingly, monoethyl ketophosphonates (compounds 3, signal around d ‫ס‬ 5) were produced in slightly larger quantities. The presence of hydroxyphosphonates 2 (as diastereomeric mixtures with 31 P NMR signals appearing at d ‫ס‬ 22-25) is not surprising if we consider the fact that trialkyl phosphites are known to reduce ␣-ketoacids [6]. Formation of bisphosphonates 4 (signals around d ‫ס‬ 20, in some cases overlapping with those derived from compound 5) might also be expected since the addition of diethyl phosphite to ␣-ketophosphonates is one of the known preparative methods of compound 4 [7,8].…”