BENZANNULATION WITH METAL CARBENE FUNCTIONALIZED ALKYNES - SYNTHESIS AND STRUCTURE OF BIMETALLIC NAPHTHOHYDROQUINONE COMPLEXES BEARING TRICARBONYLCHROMIUM AND PENTACARBONYLCARBENETUNGSTEN MOIETIES

Pentacarbonyl(1-methoxybenzylidene)chromium (1) undergoes benzannulati on upon reaction with ethyl trans-2-(phenylethynyl)cyclopropanecarboxy late (2) and pentacarbonyl[methoxy(trans (phenylethynyl)cyclopropyl)me thylidene]tungsten(0) (6) with surprisingly high regioselectivity (>97 /3) but lower diastereoselectivity (60-62% de) to give pairs of naphth ohydroquinone complexes 3/4 and 7/8 as 4:1 mixtures of diastereomers a rising from Cr(CO)(3) coordination to one or the other diastereotopic face of the naphthalene skeleton. The minor diastereomer (R(p),S-p, 1R S,2RS)-1,2,3,4,9,10-eta(6)-tricarbonyl[ethyl phthalen-3-yl)cyclopropan ecarboxylate]chromium-(0) (4) and the major diastereomer ,2SR)-pentaca rbonyl{{trans-2-[1,2,3,4,9,10-eta(6)- en-3-yl]cyclopropyl}methoxymethy lidene}tungsten(0) (7) have been characterized by X-ray analysis.