Abstract
The reaction between CpW(CO) 3 Na and 1-chlorohex-2-en-4-yne (1; cis/trans = 1/4) gave CpW(CO) 3 (η 1 -hex-2-en-4-yn-1-yl) (2) in good yield (cis/trans = 1/4). The cis/trans isomers of 2 were separated on a silica column at 0°C. Treatment of the trans isomer 2a with TCNE gave the [3 + 2] cycloaddition product exclusively to retain the η 1 -allyl activity. Addition of CF 3 SO 3 H (1.1 equiv) to 2a in cold diethyl ether in the presence of CH 3 OH gave CpW(CO) 3 -(η 1 -trans-4-oxo-2-hexen-1-yl) (5) in 61% yield. Stirring of 2a with RXH (RXH = H 2 O, MeOH, Me 2 CHCH 2 NH 2 ) in THF over Florisil at 30°C led to a new carbonylation to give CpW(CO) 2 -(η 3 -1-syn-COXR-1-anti-Me-3-syn-vinylallyl) compounds (RX = OH (6), MeO (7), Me 2 CHCH 2 -NH (8)) in 52-18% yields. The reaction of CpW(CO) 3 Na and 1-chloro-8-hydroxy-2-octen-4-yne gave the corresponding η 1 -allyl compound which on a silica column produced the intramolecular alkoxycarbonylation product 13 in moderate yield. In the presence of BF 3 ·Et 2 O, compound 7 reacted with aldehydes and unsaturated enones to give η 4 -diene salts, which after demetalation by Me 3 NO liberated organic products in 40-55% isolated yields. © 1995 American Chemical Society.