Isoxazole annelation

Hydrogenolysis of methylenediisoxazoles have been useful in preparing substituted resorcinols and aminophenols (7). The isoxazole annelation reaction (71,89,90,91,103) is well suited to the synthesis of steroids and other complex molecules. [Pg.140]

Isotetralin, 54, 11 ISOXAZOLE ANNELATION REACTION 1-METHYL-4,4a,5,6,7,8-HEXA-HYDRONAPHTHALEN-2 (3H) -ONE,... [Pg.131]

The isoxazole annelation reaction2,3 is a general method for fusing a new cyclohexanone ring onto an existing system and is complementary to the well-known Robinson annelation.4 It has several major advantages ... [Pg.75]

Since a wide range of 3-substituted-4-chloromethylisoxa-zoles can be easily prepared, the isoxazole annelation sequence allows one to construct a variety of substituted cyclohexenone systems. [Pg.75]

A fuller account of Stork s synthesis of the unsaturated tricyclic diketone [see (7) on 1, 277] is given in a communication of 1967.3 Another communication4 discusses the mechanism of the isoxazole annelation. [Pg.79]

The isoxazole annelation procedure has been used also in a stereospecific synthesis of dl-D-homotesto-sterone (5) and for its conversion into (//-progesterone ... [Pg.79]

A new and highly stereoselective total synthesis of the 13 -ethyl gonane (448) which used a Stork isoxazole annelation sequence on the diene (449) has been intimated. [Pg.475]

ISOXAZOLE ANNELATION REACTION l-METHYL-4,4a,S,6,7,8-HEX AHYD RONAPHTHALEN-2(3H)-ONE, 53, 70... [Pg.74]

The 4-(chloromethyl)isoxazole 13, which is readily accessible from 3,5-dimethyloxazole, serves as a C4-building-block in annulations to cycloalkanones (isoxazole annelation according to Stork). The primary step is alkylation leading to product 14, a masked triketone. On hydrogenation, the isoxazole ring is reductively opened and cyclization via the enaminone 15 leads to the enamine 16. On treatment with sodium hydroxide, this is converted into the bicycloenone 17 by hydrolysis, acid fission of the y dicarbonyl system and an intramolecular aldol condensation (analogous to a Robinson annu-lation) ... [Pg.143]

Sandmeyer synthesis (isatin) 145 Schmidt-Druey synthesis (pyridazine) 461 Schollkopf synthesis (oxazole) 173 Sharpless-Katsuki epoxidation 24 Shaw synthesis (pyrimidine) 468 Skraup-Doebner-Miller synthesis (quinoline) 400 Smiles rearrangement 446 Sommelet-Hauser rearrangement 136 Staudinger reaction 53 Steglich reagent (DMAP) 348 Stork isoxazole annelation 191... [Pg.632]

A different but also elegant approach led to dl-8-azaestrone methyl ether and dl-l8-nor-D-hano-8-azaestrone methyl ether. Also synthesized were 8,13-diaza-l8-norestrone methyl ethers emd 8-aza-19-norpro-gesterone. A new method using the isoxazole annelation and having the... [Pg.310]

An isoxazole annelation reaction has been utilized to prepare (inter alia) dl-progesterone and d1-homotestosterone ... [Pg.323]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...