There is no doubt that Turkey had a heinous role in Syria. It accommodated the passage of terrorists, "opposition", and charlatans like John McCain. But undoubtedly, for some time, there has been an attempt to undermine Erdogan (by neocons since 2009) and this has picked up pace as of late. I think that Erdogan was perhaps not as willing lately to cooperate. The Sarin gas story has very important holes in it.
Let us not forget that it was Israel that provided the US with “intelligence” about who was responsible for the attack, and the alleged phone conversation they heard! Additionally, according to the UN report two types of rockets had been used, including an M14 artillery rocket bearing Cyrillic markings and a 330-millimeter rocket of unidentified origin – though perhaps not so unidentified. Shortly after the August incident, Foreign Policy published and made mention of these mysterious rockets which according to former UN inspectors bore a strong resemblance to a 1970’s American weapon—the SLUFAE . Although SLUFAE had been shelved, the concept was built upon by several countries—namely Israel. According to the former UN inspector, "a very similar munition was found 3-5 years ago, during one of the Israeli excursions," into Southern Lebanon”. Further, there is the strong possibility that the rockets with Cyrillic markings (attributed to the Soviets) can be traced back to the “Bear Spares” program.
The Bear Spares program was devilishly clever in that it armed conflicts with captured weapons (such as Iraq). Both Israel and Egypt made the "Bear Spares" program feasible – major contributors. Neither country has their chemical weapons under scrutiny - they have not signed the chemical weapons treaty. We have seen how Egypt under el-Sisi has become Israel's close ally against others.
As for Erdogan, the neocons continue to undermine him. See for example:
"Questions remain, however, about whether the AKP tampered with the elections. There were also power cuts in 40 of Turkey’s 81 provinces during vote counts. Alleged lost ballot boxes have also sparked public outrage on social media over election fraud. These charges, coupled with ongoing corruption allegations, will continue to create headaches for the AKP, even as it celebrates its electoral success." - See more at: http://www.defenddemocracy.org/media-hit/turkeys-akp-wins-local-elections-but-challenges-remain/#sthash.krgUwmzG.dpuf
I do not like Erdogan, I am very troubled by Turkey’s role in the region, especially Syria, but I am even more troubled by this article making the rounds while Israel steals Golan oil and water and more land. I don't think Erdogan had as much to gain from an attack on Syria as some others – specifically Israel and Saudi Wahhabis.
At the same time Turkey is essential to the plan as water is needed for Israel, and is a major reason for the assault on Syria (pipelines from turkey through Syria for Israel).