Allylstannation III. Synthesis of homoallylic alcohols and 4-chloro-2,6-dialkyl-3-methyltetrahydropyrans by reactions between (E/Z)-2-butenyldichloro-n-butyltin and aldehydes
作者:Alessandro Gambaro、Andrea Boaretto、Daniele Marton、Giuseppe Tagliavini
DOI:10.1016/0022-328x(83)80131-4
日期:1983.10
(in various cis/trans isomer ratios) reacts readily with neat RCHO (R = CH3, C2H5, (CH3)2CH, and C6H5) at 25°C to give (a) linear alcohols, RCH(OH)CH2CHCHCH3 in the E and Z forms, (b) branched alcohols, RCH(OH)CH(CH3)CHCH2 in the threo and erythro forms, and (c) 2,3,4,6-tetra-substituted tetrahydropyrans (A) as a mixture of cis/trans isomers arising from the CH(CH3)CHCl bond. The maximum yields
25℃下,2-丁烯基二氯正丁基锡(以各种顺式/反式异构体比率)与纯净的RCHO(R = CH 3,C 2 H 5,(CH 3)2 CH和C 6 H 5)容易反应。得到的(a)的直链醇,RCH(OH)CH 2 CHCHCH 3中E和Z形式,(b)支链醇,RCH(OH)CH(CH 3)CHCH 2在苏式和赤式形式, (c)2,3,4,6-四取代的四氢吡喃(A),其为由CH(CH)产生的顺式/反式异构体的混合物3)CHCl键。在不存在溶剂的情况下,使用3-3.5摩尔比的RCHO /锡化合物可获得这些四氢吡喃的最大收率,而在CH 2 Cl 2中反应后的后处理则以线性醇为主要产物。线性醇的形成似乎是立体定向的,因为获得的E / Z异构体的比例与有机锡化合物中的比例相同。四氢吡喃优先形成为反式异构体。