Method of obtaining derivatives of 4 beta -/1'-alken-1'-yl/-2 xi ,5 alpha -dihydroxy-3,3 alpha beta -4,5,6,6 alpha beta -hexahydro-2H-cyclopenta(b)furan

A new method has been disclosed for obtaining derivatives of 4 beta -/1'-alken-1'-yl/-2 xi ,5=-dihydroxy-3,3a beta ,4,5,6,6a beta -hexahydro-2H-cyclopenta [b] furane useful in the synthesis of prostaglandins or their analogs, and a method for obtaining new sulphonyl initial compounds of the general formula 4, in which Z denotes a hydrogen atom or a protective group, Y denotes a group of the formula =CHOZ1, in which Z1 has the meaning stated for Z, whereby protective groups Z and Z1 may be the same or different, and Ar denotes optionally a substituted aryl group. In the method according to the invention the new sulphonyl derivative of the general formula 4 is alkylated with an electrophilic agent comprising: carbonyl derivatives, oxiranes and halohydrins or their derivatives; the alkylation product is transformed into derivatives of 4 beta -/1'-alken-1'-yl/-2 xi ,5 alpha -dihydroxy-3,3a beta ,4,5,6,6a beta -hexahydro-2H-cyclopenta[b] furane in reactions which ensure obtaining a double bond C13-C14. New sulphonyl initial compounds of the general formula 4 are obtained from lactone of the general formula 11, in which Z has the above stated meaning and L DEG denotes a leaving group, which is transformed into a sulphide; the obtained lactone-sulphide is reduced to lactol, and thereafter lactol-sulphide is oxidized to the sulphonyl derivative.