Leland Stanford Junior University

William S Johnson

Michael B Gravestock

Leonard A Bunes

Grant E Dubois

Paul A Bartlett

Method and compounds are provided for use in the synthesis of steroids wherein a polyolefin is provided having an initiating group having a chalcogen atom in juxtaposition to a double bond, so as to be capable of bond formation to close to form a ring and having a terminating group involving pi unsaturation (a double or triple bond) conjugated to an aromatic ring. Upon acid catalysis, sigma bonds are formed through the interaction of a carbocation formed at the carbon atom bonded to the chalcogen atom and the double bond intermediate the initiating group and the terminating group, which close to form rings of a steroid nucleus, the carbocation interacting with the pi unsaturation conjugated with the aromatic group and being captured by a nucleophile present in the acidic reaction medium. The resulting steroid product may then be modified in known ways to produce known steroids.

Synthesis of steroids

Polyenine compounds are provided having the naturally occurring geometry and a group which in the presence of acid initiates a carbocation cyclization to a steroid or A-nor-steroid structure, particularly the pregnane parent structure. The compounds are formed for the most part by condensation of two units prepared from readily available small molecules and are joined to form a polyenine, usually having a substituted carbocyclic ring which upon contact with a Lewis acid catalyst (includes protonic) cyclizes directly to provide the 5-membered D ring as well as substitution at the C-20 position.

Alkinyl terminating groups in biogenetic-like cyclizations to steroids

Estrogenic steroids are synthesized by combining under conditions favoring the formation of a trans-olefin, a .gamma.-arylpropanal with a 5,5,8,8-tetraalkoxy Wittig reagent. After hydrolysis of the gem-diethers, the resulting dioxo is internally condensed to form a cyclopentenone. The ketone is reduced to an oxy group and the resulting 2-(6'-arylhex-3'-enyl-1)cyclopent-2-en-1-ol or derivative thereof is cyclized to the .DELTA..sup.13,17 -estrene, preferably 17-alkyl-.DELTA..sup.13,17 -estrene with the A ring aromatized. After epoxidation, the 17-alkyl derivative is rearranged to form the 13-alkyl-1,3,5(10)-estratien-17-one. New compounds are provided as intermediates and final products.

Intermediate in the synthesis of estrone

Compositions are provided as well as methods for preparing the compositions which serve as cyclization precursors for the preparation of C-11 alkenyl substituted steroids and nor-steroids. The alkenyl group may be converted after cyclization to a variety of heterosubstituents to provide heterofunctionalized C-11 steroids and nor-steroids. The compounds are provided having an initiator group, which has a chalcoxy atom in juxtaposition to a double bond, an olefinically unsaturated linking group and a terminating group which acts to from a carbocation which reacts with a nucleophile to provide a stable product. The C-11 substituent is found to provide upon cyclization the alpha-configuration, so that the subject compounds provide a direct route to the difficultly accessible alpha-C-11 substituted steroids, or, if desired, the alpha-configuration can be inverted to the beta-configuration.

Olefinically unsaturated substituents at C-11 of steroid cyclization

Polyenine compounds are provided having the naturally occurring geometry and a group which in the presence of acid initiates a carbocation cyclization to a steroid or A-nor-steroid structure, particularly the pregnane parent structure. The compounds are formed for the most part by condensation of two units prepared from readily available small molecules and are joined to form a polyenine, usully having a substituted carbocyclic ring which upon contact with a Lewis acid catalyst (includes protonic) cyclizes directly to provide the 5-membered D ring as well as substitution at the C-20 position.

Precursor compounds are provided for use in the synthesis of 11-chalcogensubstituted steroids and nor-steroids, particularly 18-, 19- and A-nor-steroids. The compounds are acyclic or substituted polyenine with the olefinic groups having the proper geometry to provide the natural ring fusions upon cyclization. To initiate cyclization, a chalcogen atom is positioned in relation to a double bond, so that on protonation of the chalcogen atom, the resulting carbocation will interact with the double bond to form a pi bond if the cyclization initiator is carbocyclic and a sigma bond if the cyclization initiator is acyclic. Upon cyclization, it is found that the substituent at C-11 of the resulting steroid is in the alpha position. Various methods are provided for producing the cyclization precursor.

Growing community of inventors

Portola Valley, CA, United States of America

William S Johnson