Process for the preparation and uses of derivatives of esters of α-methylene-β-hydroxy acids

A process for the preparation of derivatives of esters of the formulae Ia or Ib:

• wherein
• n is an integer of 1 to 4 that does not exceed the bonding capability of a given R1 or R5;
• —E is
• —G— is
• X1, X2, and X3 are independently selected from the group consisting of halogen, alkyl, alkoxy, alkenyl, aryl, aryloxy, cyano, and hydrogen;
• R1 is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, haloalkyl, haloaryl, haloalkaryl, haloaralkyl, alkenyl, cycloalkyl, amino, xanthanyl, sulfinyl, sulfonyl, aryl, acyl, oxyalyl, and aroyl;
• R2 is selected from the group consisting of hydrogen, halogen, alkyl, alkoxy, alkenyl, aryloxy, cycloalkyl or —COOR6 where R6 is alkyl, alkenyl, cycloalkyl, aralkyl or aryl;
• R3 and R4 are independently selected from the group consisting of hydrogen, halogen, hydroxy, alkyl, alkoxy, acyloxy, cycloalkyl, aryloxy, aralkyl, and aryl;
• R5 is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, haloalkyl, haloaryl, haloalkaryl, haloaralkyl, alkenyl, cycloalkyl, aryl, xanthanyl, sulfinyl, sulfonyl, aryl, acyl, oxyalyl, and aroyl;
• and
• A is selected from the group consisting of oxygen, sulfur, and NR7 where R7 is selected from the group consisting of hydrogen, alkyl, alkaryl, aralkyl, haloalkyl, haloaryl, haloalkaryl, haloaralkyl, alkenyl, cycloalkyl, and aryl;
• wherein the process comprises reacting said ester with:
• A) at least one Lewis acid or base and, optionally, a stoichiometric amount of mild hydride in the absence of a transition metal catalyst, or
• B) hydrogen in the presence of a catalyst selected from the group consisting of transition metals or their oxides, or
• C) at least one soluble catalyst selected from the group consisting of alkyl aluminums, alkyl hydrides, and soluble nickel or palladium salts.