(E)-3-[Ethoxy(4-phenylbutyl)phosphinyl]-2-propenoic acid, methyl ester → trans-6-[Ethoxy(4-phenylbutyl)phosphinyl]-3-cyclohexene-1-carboxylic acid, methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of the title compound from Example 1A (3.72 g, 12.0 mmols) in a minimum amount of toluene (ca 5 ml) was transferred to a 25×150 mm glass tube which served as a liner of a stainless steel Parr pressure bomb. The bomb and its contained tube were cooled to -78° C. and a stream of butadiene was bubbled through the mixture until the glass tube was nearly full. The pressure bomb was then quickly sealed and allowed to warm to room temperature. The bomb and its contents were then heated to 100° C. and maintained at that temperature for 24 hours, after which they were cooled to room temperature. The pressure was released from the bomb and methanol was added to the contents, resulting in a gelatinous precipitate. The precipitate was removed by filtration and the filtrate was concentrated to a clear oil (3.52 g) The oil was chromatographed on LPS-1 silica gel, eluting with ethyl acetate, to give the title compound (2.6 g, 59%, Rf 0.2).

Provenance & Evidence