NOVELTY - Preparing a boron-containing compound (II) or (IV), comprises (a) providing an alkene compound (I) or an alkyne compound (III), and (b) reacting (I) or (III) with a boronating agent in the presence of water as solvent and a catalyst system comprising copper in oxidation state (I) or (II) and at least one anion comprising carbonate (CO32-), sulfate (SO42-), nitrate (NO3-) phosphate (PO43-) , hydroxide (OH-) acetate (OAc-), tert-butoxide (Ot-Bu-) and/or oxide (O2-), where the reaction mixture is free or essentially free of organic solvent(s).    USE - The process is useful for preparing a boron-containing compound (II) or (IV), which is useful in the process of transformation of the carbon-boron bond to carbon-oxygen, carbon-nitrogen, carbon-sulfur bond and carbon-X bond, where X is fluorine, chlorine, bromine, or iodine (claimed). (II) or (IV) is useful as intermediates in the synthesis of active agents such as sitagliptin.    ADVANTAGE - The process provides boron-containing compound (II) or (IV) with high yield in a simple and environmentally friendly manner.    DETAILED DESCRIPTION - Preparing a boron-containing compound of formula (R5-B(R6)-C((R1)(R3))-CH(R2)-R4) (II) or (R5-B(R6)-C(=CH-R2a)-R1a) (IV), comprises (a) providing an alkene compound of formula (((R1)(R3))CH=CH((R4)(R2))) (I) or an alkyne compound of formula (R1a-CC-R2a) (III), and (b) reacting (I) or (III) with a boronating agent having a structure of formula (H-BR5R6) or (R6R5B-B-R5R6) in the presence of water as solvent and a catalyst system comprising copper in oxidation state (I) or (II) and at least one anion comprising carbonate (CO32-), sulfate (SO42-), nitrate (NO3-) phosphate (PO43-) , hydroxide (OH-) acetate (OAc-), tert-butoxide (Ot-Bu-) and/or oxide (O2-), where the reaction mixture is free or essentially free of organic solvent(s).    Either R1, R3, R4 = 1-12C alkyl, 6-24C aryl, 7-24C alkylaryl (all optionally substituted), or H; and    R2 = (i) 1-12C alkyl, (ii) 6-24C aryl, (iii) 7-24C alkylaryl (all optionally substituted), (iv) formyl (-CO-H), (v) oxoalkyl, oxoaryl, or oxoalkylaryl (-CO-alkyl, -CO-aryl, or -CO-alkylaryl), where the alkyl, aryl and alkylaryl are defined in (i), (ii) and (iii), (vi) alkyloxycarbonyl (-CO-O-alkyl), aryloxycarbonyl (-CO-O-aryl), alkylaryloxycarbonyl (-CO-O-alkylaryl) or vinyloxycarbonyl (-CO-O-CH=CH2), where the alkyl, aryl and alkylaryl are defined in (i), (ii) and (iii), (vii) N-unsubstituted carbamoyl (-CO-NH2) or N-substituted carbamoyl (-CO-NR1aR2a), (viii) cyano (-CN), or (ix) alkylsulfonyl (-SO2-alkyl), arylsulfonyl (-SO2-aryl) or alkylarylsulfonyl (-SO2-alkylaryl), where alkyl, aryl and alkylaryl are defined in (i), (ii) and (iii); or    R2R3, R2R4 = a 5 to 8 membered monocyclic ring, preferably a 5 to 6 membered ring, optionally including within the monocyclic ring any one of structural characteristics (v), (vi) and (vii);    R1a, R2a = alkyl, aryl or alkylaryl defined in (i), (ii) and (iii); either    R5, R6 = 1-12C alkyl or alkoxy, 6-14C aryl or aryloxy (both optionally substituted), or halo; or    R5R6 = a chiral or non-chiral 5-10, preferably 5 to 6 membered mono or bicyclic ring, where the ring is optionally substituted at least one position with 1-12C alkyl and/or 6-14C aryl;    R1a = (ia) 1-12C alkyl, (iia) 6-24C aryl, (iiia) 7-24C alkylaryl (all optionally substituted), (iva) alkyloxycarbonyl (-CO-O-alkyl) or aryloxycarbonyl (-CO-O-aryl), where alkyl and aryl are defined in (iia) and (iiia), or (va) H; and    R2a = optionally substituted 6-24C aryl.