A new reaction for the synthesis of carbene precursors from aldehydes and Cp(CO)2Fe- M+ (M = sodium, potassium)

Reduction and Condensation of Aldehydes by the Isolated Cofactor of Nitrogenase

“…The newly discovered reactivity of the isolated cofactor toward aldehydes provided a platform for us to use isotope labeling experiments to probe the mechanism of cofactor-based aldehyde reduction. The first question we asked was whether activation of formaldehyde (CH 2 O) would result in a cluster-bound hydroxymethyl intermediate via several plausible routes. − Should this be the case, the hydroxymethyl species would need to undergo a series of proton/electron transfer steps, coupled with removal of oxygen as water, to generate CH 4 that contains two substrate-derived hydrogens and two solution-derived hydrogens (Figure A). To test our hypothesis, we monitored the amount of H/D labels in product CH 4 when CH 2 O and CD 2 O were supplied as the respective substrates to D 2 O- and H 2 O-based reactions (Figure A, ①, ②).…”

Recent Advances in Synthesis of Cyclopropanes

“…The 2-alkylcyclopropane derivatives are also obtained from the reaction of dimethyl malonate and cyclic sulfates derived from alkane-1, 2-diols (equation 135) 301 . Asymmetric synthesis of stereospecifically deuterium-labeled 1-aminocyclopropanecarboxylic acid has (134) (135) been achieved by using a bis-lactim ether, cyclo[α-methyl-Phe-Gly] as a chiral source (equation 136) 302 . The reactions of active methylene compounds with 1,4-dihalo-2-alkenes usually provide vinylcyclopropane derivatives via allylic rearrangements in preference to cyclopentene derivatives 286 Oxiranes can also be used as the cyclopropanation reagents, provided that the intermediate alkoxides or alcohols are sulfonated prior to the second cyclization step.…”

“…cis selectivity (equation82) 135 . Intramolecular alkylidene transfer reaction of iron carbenoid is also investigated 136 .…”

Organoiron Compounds for Selective Organic Transformations

“…Upon treatment with trimethyloxonium tetrafluoroborate, the corresponding cationic iron carbene complexes are obtained as intermediates, which undergo More recently, the synthesis of iron carbene precursors 138 from aldehydes and sodium ferrate 2 was described. 85 The alkoxides obtained at -78 °C were trapped with chloro trimethylsilane to furnish the (siloxyalkyl)iron complexes 138 in 48-78% yield after purification (Scheme 41).…”

“…For reactions carried out at higher temperature the dimerization of aromatic aldehydes furnishing carboxylic esters 139 was reported by Yamashita et al 86 Treatment of 138 with 1.1-1.7 equiv of trimethylsilyl triflate at -78 °C in the presence of alkenes (2-4 equiv) leads to the cyclopropanes 140 with high cis selectivity in 38-88% isolated, unoptimized yield. 85 Pinacol silyl ethers 141 can also be prepared from the complexes 138 by thermodecomposition at 60 °C in 48-88% yield (Scheme 42). 87 The only byproduct formed in these reactions is the dimer 1 (see,…”