Stereoselective synthesis of (E)-vinylboronic esters via a Zr mediated hydroboration of alkynes

A process for a Zr-mediated hydroboration of alkynes comprising:

• reacting a substituted terminal alkyne of formula (I) with a compound of formula II:
• Without a solvent or in an inert solvent in the presence of bis(cyclopentadienyl)zirconium chloride hydride and an amine at temperatures of about 20-150° C.,
• to obtain a compound of formula (III):
• wherein:
• X is a divalent group comprising an alkyl, an aryl or a heteroaryl;
• R1 is an alkyl, wherein two R1 groups can optionally form a 5-12 membered mono-cyclic or bicyclic ring;
• Y is a H, an alkyl, an alkenyl, an aryl or heteroaryl, halogen, CN, NH2, CO2H, N3, CHO, CF3, OCF3, OR2, OSi(R2)3, S(O)mR2, OS(O)mR2, Q, OR3Q, NR2S(O)mR2, OR3OR2, wherein R3 and R2 together may optionally form a heterocyclic ring, OR2Q, N(R2)R3OR2, N(R2)R3Q, NR2C(O)R2, C(O)R2, C(O)OR2, C(O)Q, OC(O)R2, OC(O)Q, NR2C(O)R2, NR2C(O)OR2, NR2C(O)Q;
• m=0-2;
• R2 is a H, an alkyl, an alkenyl, or an aryl optionally substituted by an alkyl;
• R3 is a divalent alkyl, or an alkenyl;
• Q is NZZ′ or N(O)ZZ′;
• Z and Z′ may be the same or different group comprising, a H, an alkyl, an alkenyl, an aryl or heteroaryl, wherein Z and Z′ taken together with the nitrogen to which they are attached may form a heterocyclic ring.