Microwave assisted preparation of C(1)-C(11) oxygen-bridged pregnanes

ALVAREZ, LAUTARO D.; SONEGO, JUAN M.; VELEIRO, ADRIANA S.; BURTON, GERARDO

STEROIDS

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2011 p. 1458 - 1464

0039-128X

1,11-Epoxysteroids may be obtained by an intramolecular remote functionalization using Suarez reagent (diacetoxyiodobenzene/I2) and irradiation with visible light. We have found that photolysis with visible light may be advantageously replaced by microwave irradiation to prepare 1,11-oxygen bridges resulting in higher yields and shorter reaction times especially in the case of sensitive substrates. Both methodologies were compared on a set of representative 11-a-hydroxypregnanes (3, 8, 10 and 11).2) and irradiation with visible light. We have found that photolysis with visible light may be advantageously replaced by microwave irradiation to prepare 1,11-oxygen bridges resulting in higher yields and shorter reaction times especially in the case of sensitive substrates. Both methodologies were compared on a set of representative 11-a-hydroxypregnanes (3, 8, 10 and 11).