Catalyst and process for ring opening polymerization

A process for stereospecific synthesis of aliphatic esters of Formula X:

• wherein:
• R31 is selected from C1-4 alkyl, C3-8 saturated or unsaturated alkyl, C3-8 branched or cyclo alkyl, (CH2)0-3 aryl, allyl, and —COO—R32;
• R32 is selected from C1-C4 straight chain alkyl, C3-8 branched alkyl, C3-8 cyclo alkyl, C6-10 aryl, C4-10 heteroaryl, and Si—(C1-C4 straight chain alkyl)3;
• “p” and “q” independently represent a number from 1 to 100;
• and
• “z” represents a number from 2 to about 200;
• said process comprising:
• (a) contacting a compound of Formula II
• with an alcohol, an optional ligand, and a compound of Formula I
• wherein:
• R1a, R1b, R1c, and R1d independently at each occurrence are selected from H, C1-C4 straight chain alkyl, C3-10 branched alkyl, C3-10 cyclo alkyl, C1-C4 straight chain alkyl substituted with up to four aryl groups, C3-10 branched alkyl substituted with up to 4 aryl groups, C3-10 cyclo alkyl substituted with up to 4 aryl groups, alkoxy aryl, thio-alkoxy, thio-alkoxy aryl, C6-10 aryl, C4-10 heteroaryl, halide, alkoxy, C(O)OC1-4 alkyl, N(R14)2, aryl-oxy, and halo-alkyl;
• R2 is selected from H, branched alkyl, alkyl, alkyl-aryl, silyl-(R31)3, alkyl-silyl(R31)3, and optionally substituted aryl;
• R3 is selected from C(R13)3, N(R13)2, OR13, and SR13;
• R4 independently at each occurrence is selected from
• M is selected from rare earth group of elements and group 13 elements;
• “n” represents an integer from 1 to 4;
• “q” represents an integer from 0 to 6;
• R13 independently at each occurrence is selected from OCH(aryl)2, C1-C4 straight chain alkyl, C3-8 branched alkyl, C3-8 cyclo alkyl, alkoxy aryl, thio-alkoxy, thio-alkoxy aryl, C6-10 aryl, C4-10 heteroaryl, halide, alkoxy, primary amine, tertiary amine, aryl-oxy, Si—(C1-C4 straight chain alkyl)3, SiH—(C1-C4 straight chain alkyl)2, and halo-alkyl;
• R14 independently at each occurrence is selected from C1-C4 straight chain alkyl, C3-8 branched alkyl, C3-8 cyclo alkyl, C6-10 aryl, C4-10 heteroaryl, C(O)—C1-C4 straight chain alkyl, C(O)—C3-8 branched alkyl, C(O)C3-8 cyclo alkyl, C(O)—C6-10 aryl, C(O)—C4-10 heteroaryl Si—(C1-C4 straight chain alkyl)3, SiH—(C1-C4 straight chain alkyl)2, and halo-alkyl;
• R21a, R21b, R21c, R21d, R21e, and R21f independently at each occurrence are selected from NO2, CN, CHO, COOH, CONH2, Cr—C4 straight chain alkyl, C3-8 branched alkyl, C3-8 cyclo alkyl, C6-10 aryl, C4-10 heteroaryl, C(O)—C1-C4 straight chain alkyl, C(O)—C3-8 branched alkyl, C(O)C3-8 cyclo alkyl, C(O)—C6-10 aryl, C(O)—C4-10 heteroaryl Si—(C1-C4 straight chain alkyl)3, SiH—(C1-C4 straight chain alkyl)2, H, N(R26)2, OR2S, and halo-alkyl;
• R22, R23, and R24 independently at each occurrence are selected from substituted and unsubstituted amines, from C1-C4 straight chain alkyl, C3-8 branched alkyl, aryl, heteroaryl, C3-8 cyclo alkyl, CR13, (CH2)1-6P(O)(R25)3, and N(R13)2;
• R25 represents alkyl or aryl;
• R26 represents alkyl;
• and
• R27 and R28 independently at each occurrence is selected from O—R26, halogen, H and C1C4-alkyl;
• to form a mixture, and
• (b) agitating said mixture at a temperature ranging from about −50° C. to about +50° C. from about 5 mins to about 48 hours to yield a compound of Formula X.