Process for producing 1,2-trans-glycoside compound

A 2-phosphonoyl-1,2-transglycoside compound of the formula (3) comprising:

• R4, R5 and R6 are the same or different and are each a protective group for the saccharide hydroxyl group,
• E is methylene or a carbonyl, and
• A is
• Wherein R2 and R3 are the same or different and are each an alkyl group having 1 to 4 carbon atoms or an aryl group optionally substituted, or R2 and R3 are connected via an alkylene group having 2 to 4 carbon atoms, further wherein the alkylene group is optionally substituted with an alkyl group having 1 to 4 carbon atoms, or optionally comprises an intervening phenylene, and m and n are each an integer of 0 or 1;
• Q2 is an alkyl having 1 to 4 carbon atoms, a cycloalkyl comprising 5 to 8 carbon atoms, optionally substituted, or one of the following groups
• wherein L1 is a group —OA', —OG or —N(J1)(J2), A1 is a group shown below, G is a protective group for the saccharide hydroxyl, and J1 and J2 are each a hydrogen atom or a protective group for amino
• R2′ and R3′ are the same or different and are, each alkyl comprising 1 to 4 carbon atoms or aryl optionally substituted, or R2′ and R3′ are combined with each other to form an alkylene having 2 or 4 carbon atoms, further wherein the alkylene is optionally substituted with alkyl having 1 to 4 carbon atoms, or optionally comprises an intervening phenylene, m′ and n′ are each an integer of 0 or 1,
• Z1 is a group —S—R1′, a group —SO—R1′, a group —Se—R1′, a group —O—C(═NH)CX'3, a halogen atom, an alkoxyl, an alkenyloxy, a group —P(OR1′)3, a group —PO(OR1′)3 or —OG1, R1′ is an alkyl comprising 1 to 20 carbon atoms, an aryl optionally substituted or a heteroaromatic group, X′ is a halogen atom, G1 is a protective group for the saccharide hydroxyl,
• R7, R8 and R9 are the same or different and are each a protective group for the saccharide hydroxyl group, and E1 is methylene or a carbonyl.

A 2-phosphonoyl-1,2-transglycoside compound of the formula (3a) comprising:

• R4, R5 and R6 are the same or different and are each a protective group for the saccharide hydroxyl group, E is methylene or a carbonyl, and A is
• wherein R2′ and R3′ are the same or different and are each alkyl comprising 1 to 4 carbon atoms or aryl optionally substituted, or R2′ and R3′ are combined with each other to form an alkylene having 2 or 4 carbon atoms, further wherein the alkylene is optionally substituted with alkyl having 1 to 4 carbon atoms, or optionally comprises an intervening phenylene, and m′ and n′ are each an integer of 0 or 1;
• and Q2a is one of the groups given below,
• A1 is
• R2′ and R3′ are the same or different and are each alkyl comprising 1 to 4 carbon atoms or aryl optionally substituted, or R2′ and R3′ are combined with each other to form an alkylene having 2 or 4 carbon atoms, further wherein the alkylene is optionally substituted with alkyl having 1 to 4 carbon atoms, or optionally comprises an intervening phenylene, m′ and n′ are each an integer of 0 or 1;
• R7, R8, R9 are the same or different and are each a protective group for the saccharide hydroxyl group,
• E1 is methylene or carbonyl,
• Z2 is a group —S—R1′, a group —SO—R1′, a group —Se—R1′, a group —O—C(═NH)CX′3, a halogen atom, an alkoxyl, an alkenyloxy, a group —P(OR1′)3 or a group —PO(OR1′)3;
• R1′ is an alkyl comprising 1 to 20 carbon atoms, an aryl optionally substituted, or a heteroaromatic group, and
• X′ is a halogen atom.