Reaction of dialkyl- or diaryl-trans-(3,4-epoxycyclopentyl)phosphine oxides 2 with the lithium derivative of methyldiphenylphosphine oxide gives a mixture of (+/-)-t-4- and (+/-)-c-4-(disubstituted phosphinoyl)-t-2-(diphenylphosphinoyl-methyl)-r-1-cyclopentanol derivatives 13a-c and 16a-c, which could be obtained in pure form by separation of the corresponding acetates 14a-c and 17a-c followed by methanolysis. Compounds 13b and 16b were transformed into the corresponding dehydroxy derivatives 19 and 21 through the Barton procedure. Additionally, 16a was transformed into a diastereomeric mixture of carbamates 22 and 23 on reaction with (S)-alpha-phenylethylisocyanate which could be separated by repeated crystallization. The relative configuration of compounds 13b, 17a, 21 and 22 was established by X-ray diffraction analysis. (C) 2002 Elsevier Science Ltd. All rights reserved.
Straightforward regio- and stereo-selective synthesis of t-2-[(diphenylphosphinoyl)methyl]-c-3-(disubstitutedphosphinoyl)-r-1-cyclopentanols
A 3-step, regio- and stereo-selective, high-yielding synthesis of t-2-[(diphenylphosphinoyl)methyl]-c-3-(disubstitutedphosphinoyl)-r-1-cyclopentanols (8a–d) is described. Reaction of epoxides 2a–d and/or 5a–d with the lithium derivative of methyldiphenylphosphine oxide (9) gave cyclopentanols 8a–d. Base-catalyzed rearrangement of epoxides 2a–d and/or 5a–d led to 3-(disubstitutedphosphinoyl)cyclopent-2-en-1-ols