Synthesis and electrophilic reactivity of [{η 5-1- N(CH 2CH 2O) 3Si-6-Me-C 6H 5}Mn(CO) 2NO]BF 4

Abstract

[{η 5-1-N(CH 2CH 2O) 3Si-6-Me-C 6H 5}Mn(CO) 2NO]BF 4 [ 3(CO)] has been synthesized by the reaction of [{η 5-1-N(CH 2CH 2O) 3Si-6-Me-C 6H 5}Mn(CO) 3] ( 2) with NOBF 4. The addition of phosphines or phosphite to 3(CO) yielded [{η 5-1-N-(CH 2CH 2O) 3Si-6-Me-C 6H 5}Mn(CO)(L)NO]BF 4 [ 3(L)] (L = PPh 3, PMePh 2, PHPh 2, and P(OPh) 3). Addition of excess P(OMe) 3 to 3(CO) led to [{η 4-1-N(CH 2CH 2O) 3Si-5-P(O)(OMe) 2-6-Me-C 6H 5}-Mn(CO) 2NO]′ ( 4), which decomposed to liberate the 1,3-eyclohexadiene derivative of silatrane 5. Hydride addition to 3(CO) gave [{η 4-1-N(CH 2CH 2O) 3Si-6-Me-C 6H 6}Mn(CO) 2NO] ( 6) and [{η 4-6-Me-5-N(CH 2CH 2O) 3Si-C 6H 6}Mn(CO) 2NO] ( 7). After removal of the manganese moiety from 6 and 7, 1,3-cyclohexadiene derivatives of silatrane, 8 and 10, were obtained. Treatment of 3(CO) with the carbanion of ethyl cyanoacetate and then Me 3NO in refluxing benzene gave the cis-disubstituted cyclohexadiene derivative of silatrane, 12. Addition of LiCH 2CN to 3(CO) yielded [{η 5-1-N(CH 2CH 2O) 3Si-6-Me-C 6H 5}Mn(CO){C(O)CH 2CN}NO] [ 13(C(O)CH 2CH 2CN)] which rearranged to the diene complex, presumably possessing an endo substituent. The diene compound afforded the trans-disubstituted cyclohexadiene derivative of silatrane 15(C(O)CH 2CN), LiCH 2CO 2 i Pr, and LiCH 2CO 2 tBu also attacked the CO in 3(CO), ultimately affording 15 (C(O)CH 2CO 2 iPr) and 15 (C(O)CH 2CO 2 tBu respectively.